I'd like to share this adventure with you. It's one of the better things I've made and it worked fine when I was running it. 
Hope posting it does not violate the rules... 
LOST IN THE STORM
Wherein the heroes go on a quest to rescue a missing planewalker and face both the madness of a plane and of its inhabitants.
Lost in the Storm is a short adventure for characters of level 9-10.
BACKGROUND
A group of planewalkers led by an aasimar by the name of Aruar went after the dark of Harmonica, a place of legend in Cocytus, the second layer of Pandemonium where the secret is said to be found to travel the planes without magic or portals. Aruar and his three companions, the humans Korrin and Selesha, and the bariaur Mallak were searching for a particular portal in Pandesmos to get to Cocytus.
Unfortunately, the sods ended up as the prey of Nixxalk, a blue slaad who went to Pandemonium to boost his confi-dence in his martial prowess by slaying whatever happens to come across his path and look like a serious challenge. Ex-hausted by the attacks of the slaad they were forced to re-treat to the portal back to the cage. On their way back the berks realized, that the mage Korrin got lost somewhere in the dark. He got captured by the minions of the barmy drow wizard Zelgos. Of course, the planewalkers are clueless about that.
SYNOPSIS
After getting through the gate, the PCs fight their way through the dark and extremely windy tunnels and caves of Pandesmos and must prevent the salad from putting them in the dead-book during his sudden strikes. They find Korrin in the hands of a barmy drow and hopefully manage to bring the spellslinger back in one piece
HOOK
There is most likely just one way for the bashers to get on this ride:
While the heroes move in Sigil, it suddenly gets noisy as a howling wind starts to blow dirt and rubble through the alley and Aruar and his remaining companions tumble out of a whirling portal to Pandesmos. They beg the cutters to save their man and promise them a considerable reward, if they hesitate to do it out of sheer goodness. If they agree the heroes get goggles and earplugs from the unlucky cutters to protect them from the perils of the plane. Of course communication between bloods tends to suffer, when they can’t hear each other.
The portal’s just opening for a hour each day, so the bashers’ll better hurry up when they are going to do the deal.
If the berks refuse to help these adventurers, the story ends here.
PANDESMOS
The encounters in this adventure take place on two loca-tions. The windy tunnels of Pandesmos and the small hide-out the drow wizard Zalgos calls kip.
PANDEMONIUM FEATURES
Pandesmos looks similar to the subterranean cave systems found on the material plane. The size of the tunnels and caves ranges from small holes to spaces that would put a kingdom to shame.
Besides the winds many caves have another noteworthy feature. Streams of biting cold water run through the tunnels, sometimes even right through the air, when they are caught between the subjective gravitation of opposed walls.
Apart from the huge chambers and corridors shown on the map, there is a huge number of smaller tunnels that are not drawn in.
Floors: The floors are ragged and uneven. Therefore running through the caves proves risky. A character that tries to run or to charge has to succeed on a DC 12 Balance check or she stops and falls prone. Because the subjective directional gravity always points to the nearest wall the concept of walls and ceilings proves quite useless on this plane (see MotP).
Light: There are no natural sources of light in Pande-monium and normal fire is snuffed out in seconds. The bashers better carry sunrods with them of possess useful magic, lest they are put in the dead-book by the plane.
Winds: The ever-present cold winds are a characteristic feature of this forbidding plane. There's also always a good chance for a sod to get caught in a violent storm that rages through the tunnels and caves. See the Manual of the Planes, for example, or imagine icy storms that drive a person mad, before they smash him against the rocks.
MAPS
Here's the maps. They look a bit odd, because I am too lazy to install my scanner and made the pictures with my camera.
Pandesmos:
http://i80.photobucket.com/albums/j184/Calmar2786/Maps/pandesmos.jpg (note: 'north, or whatever passes for that on the planes, is on the right side of the page.)
The drow's kip:
http://i80.photobucket.com/albums/j184/Calmar2786/Maps/zalgos_home.jpg
Encounters
1. Windy Tunnel
The portal is located in a narrow slit between the rocks. There is no light and a strong cold wind blows through the tunnel with a deafening noise.
The cutters’ll find that the only way to go is the upper one, as the wind blows too violently to go elsewhere.
2. Vortex (EL 11)
Intense winds whirl around in this cave and hurl stone boulders through the air. The collisions between the rocks and the cavern floors create a droning rumbling that seems to increase and to ebb away from time to time.
Every creature suffers 1d8 points of bludgeoning dam-age from the sharp stones that whirl in the air each minute it stays in this area (Reflex save DC 15 for half damage).
Creature: Nixxalk, a blue slaad that came here for hunting. After chasing Aruar’s group he lost interest in the planewalkers and decided to hang around elsewhere untile he ended up here.
Nixxalk, Advanced 14 HD Blue Slaad (CR 11)
Tactic: Nixxalk stays hidden (Spot DC 20) and watches the bashers after noticing them. When the heroes discover the nasty and intend to attack him he attempts to hurl one of them away using his telekinesis ability and takes on the rest with his impressive claws. After a few rounds the slaad gives them the laugh and disappears in the darkness, leaving the cutters wondering if they scared him off, or if the crea-ture just plays with them.
Development: After Nixxalk leaves the cutters he stalks around in the darkness, staying close them and uses his darkvision to keep an aye on them. It is up to the DM to decide how much the slaad harasses the bashers. Mind you the nasty’s not actually evil, despite being at odds with the characters. Nixxalk’s here to boost his confidence in his strength, not to slaughter some helpless sods, berk! If the cutters appear to be clearly weakened, Nixxalk gains noth-ing from giving them the rest and probably goes looking for trouble elsewhere.
Ad Hoc Experience Reward: Because the conditions favor the slaad the heroes get 150% the standard XP for an EL 11 encounter, no matter when they put him in the dead-book, or if they manage to do the bolt.
"I HUNTS YOU, I EATS YOU, I KILLS YOU!"
-- Nixxalk the slaad
3. Shaft
Here the tunnel declines steeply. The wind is so strong here, that the SCs have to climb, despite the objective directional gravity (Climb DC 20). Bashers who are caught by the wind are hurled to the end of the tunnel and take 6d6 points of damage. If they are canny planewalkers they may use a rope to bind them together. In this case they can help each other with the climb check.
4. The Icy Lake (EL 0 or 11)
A huge lake of ice-cold water stretches through this vast cave and stretches along the ‘walls’ to the opposite end of the cavern. The roaring of the wind is mixed with the noise of fast flowing water.
A pale man whose gaunt body is wrapped in rags sits near the end of the shaft. He has sunken facial features and thin white hair that is spun around by the wind. The codger sits near the shore of the lake and nods back and forth while mumbling to himself. Where his eyes have been, thick scar tissue covers his had.
A cutter can try to chatter with him, when she takes him to a quiet corner. In which ‘quiet’ means to shout like an addle-coved prime thrown in the Abyss, anyway. At first the old man actually seems to listen to whatever the bashers’ll tell him. After a short time he’ll mention the ‘bridge’ in area 10 and repeatedly point out its dangers. After that the char-acters won’t get anything out of him, except for shrill laugh-ter.
Creature: On their way back, Nixxalk ambushes the bashers near the lake. This time he fights until reduced to 20 hp and retreats.
Nixxalk, Advanced 14 HD Blue Slaad (CR 11)
Tactic: See area 2.
5. Infernal Intruders (EL 11)
This cavern is very furrowed and the wind creates a shrill yowling sound.
A group of baatezu has come here, hoping to find single demons to slaughter.
Creatures: Two Osyluths and two barbazu are moving through the cave.
Bone Devils (2): hp 95 each; MM 52.
Bearded Devils (2): hp 45 each; MM 52.
Tactic: The devils are never disinclined to take up a fight with a group of mortals and readily attack the cutters. The bearded devils fly into their battle frenzy and move into close combat. If the osyluths win initiative they create major images of one additional barbazu, each. Otherwise they use their invisibility and teleport to physically weak bashers, or in a flanking position. If the heroes prove too strong the bone devils attempt to summon lemures for support. The bone devils retreat when the the bashers slay the barbazu and are going to kill them, too.
It’s a bet that the osyluths hunger to avenge the humiliation of being defeated by some ordinary mortals. Trouble’s coming, berks.
6. Floating River
Right across the middle of a side tunnel, a 50 feet wide river flows through the air, gushing into the lake.
7. Blind End
The tunnel is blocked be huge boulders that probably have been rolled here by the wind. Here the last fight between the aasimar’s group and Nixxalk took place. Frozen and dries stains of blood cover the ground of the cave (Survival DC 15). Hours later the minions of Zelgos found Korrin’s un-conscious body lie here on the ground. They brought him and his equipment to the barmy drow’s kip.
Treasure: Parts of Korrin’s gear lie scattered and destroyed on the ground. Most of the stuff is worthless, but among the trash the cutters can find a 50 silk rope.
8. Waterfall (EL 11)
The Tunnel ends in shaft that vertically crosses it. Water flows down that tunnel, in an angle of nearly ninety degrees, filling the tunnel the bashers are coming through with fog before continuing to flow in the darkness.
Creature: The blue slaad Nixxalk attacks the heroes a second time here.
Nixxalk, Advanced 14 HD Blue Slaad (CR 11)
Tactic: See area 2.
9. Bloody Traces
The lake’s water flows through this tunnel, alternating its course along each side of the tunnel, or crossing it midair.
Near the mouth of the river the stones are covered with blood (Survival DC 20). Here the poor sod Korrin got car-ried by Zalgos' minions to their master’s lair.
10. Abysmal Chasm (EL 12)
A broad abysm that appears to have neither a bottom nor a ceiling extends to both sides into the darkness. The wind howls with immense force through the chasm, hurling boulders as big as an ox against the rock walls as if they were grains of sand. A natural bridge of rock spans the chasm. It is approximately 40 feet wide and 600 feet long.
The cutters can find a side of the bridge, where the wind is pressing them against the ground, making it possible to cross it. Well, possible’s not easy and it’s still a good piece of work to crawl up the bridge, since they’re technically climbing through the vast space and the bridge’s gravity ain’t the stronges the bashers’ll find on this plane, either.
Each minute a bashers spends here she must succeed on a DC 18 Will save or be struck by confusion (as the spell) for 1d4+1 rounds, despite wearing earplugs. If a cutter’s addle-coved enough to forgo the earplug the save DC rises by then for this berk. Furthermore each round there is a 5% chance to be struck by flying pieces of rock for 3d6 points of bludgeoning damage.
To make things worse a basher’s to succeed on a DC 20 Fortitude save each minute he’s crawling over the bridge. On a failure he’s grasped by the howling wind and gets hurled in the darkness. A cutter’s got to use a rope (mayhap Korrin’s from area 7) to tie himself to his companions. For each blood he’s connected to the save DC is lowered by 2. If a tied sod’s caught by Pandesmos' merciless grip it requires a DC 20 Strength check of her friends to pull her back. Here, too, each additional member of the group can aid in making the check.
If a berk’s making the trip without using a rope, she’s almost certainly put in the dead-book when she looses her hold here.
11. Crossing River
In the middle of this cavern a river runs out of the ‘ground’ (from that part of the cave that appears as ground on the first glance unless the cutters have spent their time running around the walls).
12. End of the Tunnel (EL 9 and 7)
This area is opened to the chasm and also ploughed through by the stormy winds. A single corridor leads out of the area. The corridor is clearly artificial and in this area the gravity is directed in the direction of only one wall. At the end of the corridor is the entry to the mad drow’s kip.
Creatures: Eight wights lurk near the entry to Zalgos’ hideout. They are the barmy remnants of poor sods that were killed by the maddening winds of Pandemonium.
Wights (8 ): hp 26 each; MM 255.
Trap: At the beginning of the corridor leading to Zal-gos’ kip a magical trap that seems to ignore the winds is drawn on the floor to keep unwanted intruders off. Unless the heroes happen to be undead they can’t benefit from drow wizard’s bad experiences with the locals and need the password to get safely past it. Otherwise they have to get past the trap in the traditional adventuring kind of way.
Summon Monster VI Trap: CR 7; magic device; prox-imity trigger (alarm); no reset; spell effect (summon monster VI (Chaos Beast [MM 33]), 11th-level wizard), Search DC 31; Disable Device DC 31.
ZALGOS' HOME
The drow wizard Zalgos, the descendant of drow outcasts that were banished to Pandemonium millennia ago, lives in this small complex. For Years he’s working on a way to give Pandesmos the laugh to get to a more hospitable plane. However, he’s been driven mad by Pandemonium’s winds many years ago, wherefore his work’ only marginally pro-ceeding. Besides him two goblins and a hobgoblin live here. They favour Zalgos’ insane mood swings over the cutting winds of Pandesmos and serve the drow. These minions found Korrin and brought him to their master.
A. Workshop (EL 5-8 )
This walled room is empty, except for a pile of junk the goblins have found in the tunnels of Pandesmos. None of the items is useful or of any value.
Zalgos has cast a permanent alarm spell on the right door that warns him instantly, if the door is opened without saying the password ‘quarraz’. The goblins have learned that it’s not the best idea to activate the alarm unintention-ally. Therefore the drow can be sure that trouble’s coming when he’s alerted.
Creature: A hobgoblin is in this room. Should the cutters have managed to open the door without making any noise the hobgoblin sits on a stool and sharpens his blade.
Hobgoblin, 5th-level NPC Fighter: hp 47; DMG 117.
Goblin, 5th-level NPC Rogues (2): hp 25 each; DMG 123.
Tactic: The hobgoblin alerts the rogues in room B with a shout and attacks the heroes. The goblins arrive 1d2 round later and concentrate on flanking an enemy.
Development: As soon as Zelgos is warned by his alarm spell that intruders have entered his case, he casts his protective spells. After a few minutes he starts searching the complex for whoever made it uninvited to his kip, if the cutters don’t show up in his private rooms, first.
B. Goblin Lair (EL 0 or 7)
Four dirty and used up mats lie on the floor of this dark room. Here do the goblins take kip. One of the mats is abandoned since the goblin that was using it was made wormfood when he crossed the bridge and got caught by the wind.
Creatures: Two goblin rogues are staying here, unless they have already been defeated in room A by the bashers.
Goblin, 5th-level NPC Rogues (2): hp 25 each; DMG 123.
Tactic: The two rogues try to flank a foe and attack him, until he’s down before switching their target.
C. Beast Pen (EL 3)
This narrow pen is closed by a strong iron grating. Despite its stench the room is relatively clean.
Creature: A howler is kept here. The goblins use it as mount when they are on patrol in the tunnels.
Howler: hp 39; MM 155.
D. Birdcage
On the right side of the short corridor are two cages. In the backmost lies an unconscious man whose body is wrapped in ragged clothes that are covered in brown blotches of dried blood.
The man’s Korrin who was brought here by the goblins. Zalgos has not yet spoken to him, but the drow picked the items he carried on his body, as well as his spellbook. The drow hopes to find something useful for his escape from this plane.
Development: When the bashers put Korrin together (Heal DC 15) he can tell them the reason he and his companions went here in the first place. If the cutters are wondering how to get back to Sigil again, he tells them, that the portal’s just opening for a few hours a day, in this week, so they should not dally too long.
E. Kitchen
The rearmost corner of this room is bare rock and a little well of fresh, cold water. Otherwise there are only a small table and a fireplace. An illusory wall covers the passage to room F.
F. Trapped Room (EL 7)
This room is empty.
Trap: On the floor of this room are well-hidden magical writings that belong to a magical trap that summons a Large earth elemental, if someone neters the room without saying Zalgo’s password (tha same as in room A).
Summon Monster VI Trap: CR 7; magic device; prox-imity trigger (alarm); no reset; spell effect (summon monster VI (Large earth elemental), 11th-level wizard), Search DC 31; Disable Device DC 31.
G. Conjuration Room (EL 0 or 12)
The floor of this 30 feet wide rectangular room is covered by a huge magical circle of sand that is riddled with runes and geometrical shapes. The ceiling of the room is with 20 feet twice as high as in the rest of the complex. The drow’s trying to build his own portal here to get him elsewhere.
Creature: Zalgos, a skinny dark elf with sunken fea-tures and pale white hair that scrubby hangs to his shoulders is in this room, unless the bashers managed to avoid his alarm. He wears old worn out clothing and hobbles when walking.
Zalgos CR 12
Male drow wizard 11
CE medium humanoid (elf)
Init +3 Senses darkvision 120 ft., Listen +3, Spot +2
Languages Common, Elven (drow dialect), Undercommon, Abyssal, Infernal, Slaad
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AC 22, touch 14, flat-footed 19
hp 29 (11 HD)
Resist sleep SR 22
Fort +5, Ref +8, Will +8 (+10 spells and spell-like abilities)
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Speed 30 ft (6 squares)
Melee mwk dagger +6 (1d4/19-20)
Space 5ft.; Reach 5ft.
Base Atk +5; Grp +5
Atk Options planar spellcasting (anarchic) (PH 36)
Combat Gear scrolls of cat’s grace, summon monster IV, wand of magic missile (CL 5th, 20 charges)
Wizard Spells Prepared (CL 11th):
6th––chain lightning (DC 20), summon monster VI
5th––cloudkill (DC 20), command person (DC 20), extended greater invisibility
4th––bestow curse (DC 18 ), dimension door (2), summon monster IV
3rd––dispel magic (2), fly, haste, slow (DC 17)
2nd––glitterdust (DC 18 ), acid arrow (+8 ranged touch), scorching ray (+8 ranged touch) (2), summon monster II
1st––mage armor†, magic missile, protection from chaos, ray of enfeeblement (+8 ranged touch), shield†
0––mage hand, message, open/close, ray of frost (+8 ranged touch)
† already cast
Spell-Like Abilities (CL 11th):
1/day—dancing lights, darkness, faerie fire
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Abilities Str 10, Dex 16, Con 10, Int 19, Wis 8, Cha 15
SQ drow traits (MM 103), summon familiar (none at pre-sent)
Feats Augment Summoning, Eshew Materials, Extend SpellB, Scribe ScrollB, Spell Focus (conjuration)
Skills Concentration +8, Craft (alchemy) +11, Decipher Script +9, Knowledge (arcana) +19, Knowledge (dun-geoneering) +11, Knowledge (geography) +11, Knowl-edge (the planes) +17, Listen +3, Ride +4, Search +7, Spellcraft +19, Spot +2
Possessions combat gear plus ring of protection +1, cloak of resistance +2, clear spindle ioun stone, headband of in-tellect +2, masterwork dagger.
Spellbook spells prepared plus 0––all; 1st––identify, mount, resist planar alignmentPH, unseen servant; 2nd––cat’s grace; 4th––minor creation; 5th––contact other planes, precipitate breachPH; permanency; 6th––planar binding
If you don't use the Planar Handbook, simply give the wizard his 10th-level bonus feat and change the spells from that book to whatever spells you like.
Tactic: The drow is not essentially anxious to fight the cutters, when they can tell him something useful, but the winds of Pandemonium drove him barmy which becomes noticeable in his actions. When the cutters are chattering with the spellslinger, roll d%:
On a 01-05% he simply attacks the heroes; on a 06-80% he poses unnerving and partially even totally pointless questions regarding the creation of portals; on a 81-100% he simply does nothing for a while.
When a fight starts, Telgos casts his extended invisibility spell to disappear for 22 rounds and throws his spells against the heroes, preferring casters as targets, since they can rob him his advantage. Otherwise he uses area spells and summoned creatures as he sees fit. He’s not keen to die here and uses dimension door to give the bashers the laugh when they’re up to box him in.
Development: The big sign on the floor is Zalgos’ try to build him a portal to leave the plane. He ain’t been success-ful so far. If a cutter succeeds on a DC 30 Spellcraft check she can help the drow to finish the gate. Where it’s up to go is in the hands of the DM.
H. Zalgos’ Bedroom
This small room ist he wizard’s bedroom. Besides a simple bed and a desk with a stool the bashers can find a shelf that’s cramped with notes written on all kinds of parchment, paper and fabric.
Creature: If the heroes didn’t activate the alarm spell in room A Zalgos can be found here sitting at his desk. He’s studying Korrin’s spellbook in order to find some clues for the construction of his portal.
Zalgos: hp 29; see above.
Tactic: As described in room G, except that the drow casts dimension door to get to his conjuration room, first.
Treasure: Korrin‘s gear (spellbook [see DMG 126], cloak of resistance+1, ring of protection +1), 2nd level pearl of power, scrolls of fireball, minor creation, mount, permanency, summon monster II, summon monster IV, wand of detect magic (40 charges), masterwork quarterstaff.
CONCLUSION
After the heroes have gone back to the portal and brought Korrin back to the Cage, they can count on having won new friends. Should they refuse to handle the spellslinger’s back to him he does not protest, but is not interested in further dealing with the basher’s either.
Another way to conclude the adventure is to help the drow to finish his work and step through. The gate can lead to whatever place suits the DM.
"Where's the stats for the slaad?!"
I was going to post it, but, as the modrons can certify, slaadi are "Product Identity" by Wizards of the Coast and, as such, are not released under its Open Gaming License". Guess that means, thy may not be posted.
"The bridge-part is too complicated/ your rules are silly."
It is more like a suggestion, most of all. I think it works best when you wing it, anyways.