I have no idea whatsoever if you can use any of this stuff. A whole lot of it is really just random detritus I have floating about, both in my head and on paper. Here it is, maybe you can use it.
Sinistratus Lives!
Status: Sidequest
An evil mage by the name of Sinistratus (yes, that's his name, yes, I know) obsessed with immortality has discovered the means to store his vast and unfathomably evil intellect into a high-level spell. He has disguised this spell as some powerful 'oh-wow!' enchantment, scribed it into an obscure spellbook, and hid it in a demi-plane library where several scholars have been spending time studying a certain mystical phenomenon (possibly the plane of mirrors).
His idea was that someone would eventually find the spell, commit it to memory, and then the spell--actually being nothing more than a copy of his very 'essence'--would proceed to take over their mind and convert the hapless spell-caster into a copy of himself.
All in all, it was a pretty savvy idea--just one problem.
That 'obscure book' he chose turned out to be the all-important textbook of a powerful mage, and everyone on the team ended up memorizing the spell.
Sinistratus is long dead--killed by his own creation. All that remains of his legacy is the smoldering ruins of a once-prolific library, now constantly patrolled by dozens upon dozens of low-level mages who all believe themselves to be the original Sinistratus. All of them are completely, absolutely, irrevocably barmy--and attack anyone (including each other) on sight.
This wouldn't be so bad, except that recently a group of adventurers attacked the place, fought through a lot of the Sinistratus-clones, and managed to reclaim the book (which they assumed was a high-powered spell-book) for themselves--and their mage proceeded to memorize the spell, too. Things went downhill from there.
Now there are Sinistratuses spilling out all over the Plane of Mirrors. For most of the denizens, they're little more than a nuisance--but a few of them have been managing to escape, scribing the nasty spell rattling around in their heads to scrolls and trying to spread the plague (all the Sinistratuses are obsessed with what the original Sinistratus was obsessed with--attaining immortality--and they still all 'think' that this is a good way to pull it off).
The adventurers may encounter one or two lone Sinistratuses near the beginning of the adventure without much explanation, and may only later on stumble across the vast academy filled with Sinistratuses, either because a necessary part of their quest takes them there or just out of curiousity to find out what happened. The option to destroy the original copy of the book and spell should be available, as well as a potential NPC (one of the scholars who survived) who's studying a way to reverse the process using an engineered spell that targets anyone who currently has the Sinistratus-copying spell in memory.
The Planar Tourism Board's Official Mimir
Status: Item
"Congratulations on your recent acquisition of the Planar Tourism Board's official Mimir! Inside of my skull you will find an array of useful, helpful information to aid you in your decision on whether or not to commute from the Prime Material to the Planes..."
The Planar Tourism Board's official Mimir is the perfect gift for any player freshly arriving in the Planescape mythos--it's a century out of date and absolutely brimming with misinformation (what could be better?). The best part is that it was designed by a bunch of barmy Fated who had the crazy idea of attracting Primers to the Planes to increase business by painting everything in the Planes in a positive light.
Ask it about the Spire--"Gods got you down? Tired of mages throwing around polymorphs like they were hot potatoes? Travel to the exotic Spire, home of the rilmani! No annoying, errant spells here, no sirree!"
Ask it about Carceri--"Enjoy the heartfelt sincerity of the local color, all of whom desperately want to know just what they need to do to you to convince you to never leave!"
Ask it about Gehenna--"Visit their renowned hot-springs! Bring your swimming trunks--it's always summer here!"
Ask it about Baatezu--"ERROR, NO DATA ON RECORD"
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I have more, but it's late and I'm exhausted--I'll write them up later and post them here. If you have any requests or something specific you want me to hone in on, go ahead and throw it at me.
Edit: These are both rather humor-related, but don't worry--not all my ideas are meant to be silly. Just MOST of them. D:
More junk. Just storing it here. I'll go through some of my old notebooks where I contained more of this stuff later on.
Audio Mimir
What might be a really cool stylistic touch to add to the campaign release (though it might require too much work) is to construct a 'living mimir' CD-pack (mp3 files) similar to that other release--it could be done in the style described in the Sigil Tourism Board description I have above, or take another form.
Of course, to pull it off, you'd need someone who knows a lot about audio, and plenty of available voice actors. Might be too ornate (though it'd be an awesome supplement, if you could pull it off--I can just imagine DMs playing it on a CD and letting it answer a PC's questions for them).
The Great Unknown
Philosophical Bull
As I see it, the Great Unknown has three underlying precepts; three 'noble Truths', if you'd like. Commonly, these truths may be related through the use of an allegory or fable as an instructional tool. The fable goes something like this:
The First Noble Truth:
Long ago, a man gifted in all manner that men may be gifted--mind, body, and virtue--walked the planes. Hungry for the fame his worship would bring, the Powers flocked to him like hungry wolves to win his loyalty.
Each in turn promised him all manner of gifts, but the man was uninterested. Of each Power, he asked only this: What is Truth?
"War," some said. "To destroy your enemies," said another. "To bring virtue to the planes," said yet another. And the man patiently waited until their truths had been piled before him like a heap of treasures. Then, finally, he asked: "But what is the Truth?"
And at once there was a frightful clamor as the Powers fought among one another as might petulant children. And so did the man come to know the first noble truth of the Great Unknown:
Truth cannot be found by walking another's path. You must seek it on your own terms, within yourself--it cannot be handed to you by a Power.
The Second Noble Truth:
For years, the man wandered the planes in search of Truth. He came to learn that there are many who claim to know Truth, and can shape the Multiverse by will alone to abide by their truths. But these truths are not truths at all; only fickle illusions.
He learned that if he too believed a Truth, the Multiverse could yield to the power of his belief . And so did the man come to know the second noble truth of the Great Unknown:
Belief does not define Truth--it only taints it. To understand Truth, one must first shed all that you believe.
The Third Noble Truth
In time, some came to search for Truth with this man. Some even claimed to find it--scholars and sages who had spent ages mapping the nature of the Multiverse in their heads. They told him by mastering a part, one could understand the whole--and thus they began to define laws and axioms by which the Multiverse was governed.
Yet for each law, the man found an exception. For each axiom, he found a paradox. Truth did not acknowledge man's laws. The Multiverse did not recognize the rules of its denizens. And thus did he and his people come to understand the third and final noble truth of the Great Unknown:
The Great Unknown is unknowable. To know it is to taint it into something of your own. The Great Unknown is Truth, and Truth cannot be understood--only acknowledged and accepted, forever unknown.
The Xirbur Cube
Item
These small metal cubes are ingrained with countless geometric patterns, niches, knobs, and switches. The whole thing can swivel around on itself in nearly any direction, always clicking neatly back into place in the form of a cube.
Designed by a Xaositect, the Xirbur cube is a problematic puzzlebox that is ompletely unsolvable by ordinary means. No amount of turning, twisting, clicking, pulling, or tugging will ever solve the box's scripts. Patterns will emerge, disappear, and re-emerge as would-be solvers attempt to figure out a solution, but in the end everything the box does to suggest that the character is coming close to a solution is just a false signal meant to encourage them to waste more time.
Divination spells always reveal that the box has a hollow space inside it (although whatever may be inside is sheltered against divination magic), and to all appearances the box is composed of an indestructible material. However, there is one solution: Smash the box. Despite the fact that it's made out of an apparently unbreachable material, the box will instantly fall to pieces on the spot, revealing whatever is inside. Reconstructing the box is plainly simple, as the pieces are interlocking and fit together relatively neatly.
Xaositect Thinking Cap
Item
This rather unwieldy looking metal helm, complete with whirly-gigs and tassles, fits neatly on the head and serves to completely destroy any sense of consistency your wardrobe may have. Nevertheless, some Xaositect claim it helps you think much more clearly.
While wearing the helm, the user suffers a -4 penalty to their Wisdom score. This penalty disappears once the owner removes the helm. Anyone wearing this helm while wearing a Xirbur cube immediately realizes the proper solution (smash it open).