Hello Everybody!
I'm new here, so first a few words about myself: I'm from Poland, so sorry in advance for any grammar errors. I've been using Planewalker's materials for about two years and I find this webpage very inspiring and useful 
I'm creating a PS campaing this days and I'm looking for tips about roleplaying and describing some NPCs that I have created or incorporated into this scenario. I've got quite clear ideas about their personalities and habits, but I want to make them as interesting as possible and because of that I'm searching for others' concepts. Just have a quick look at descriptions below and - if You have any ideas about things that can add flavour to these characters, write about them, please
As I'll be creating next parts of campaing, I'll be posting here futher descriptions.
Cronus: He'll be players' "employer" - he'll have sent them in search for Sisyphus, who had been liberated by some unknown force (main plotline of campaing).
I see him as a creature of pure live, ideal but amoral (not immoral or evil, however - rather CN) human. He loves interesting people, good jokes and art, but when he goes bananas, he is worse than most of tanar'ri. He is at the same time quite depressed - as an imprisoned lover (or, to call spade a spade, personification) of freedom, he considers his existence a torture. With him, I'm looking mostly for an interesting way of describing him and Mount Ortys - do you have any interesting descriptions? Any pictures, maybe?
Parrafaire: Players may get important clues from this serpentine power if they will pass his tests.
Any hints about describing him and his divine splendor would be even more welcome here than in the case of Cronus. When it comes to personality, I'd compose his psyche of three elements: respect for three rules of the Multiverse (Unity of Rings etc.), belief that mind is most powerful, complex and beautiful thing in all Planes and that every thing must be won in one way or another (which will be, in fact, his interpretation of Unity of Rings).
Mammy Pogodowoskowa*: Night Hag living in Carceri, she has got some information about Sisyphus... and she'll try to sell PCs to Orcus' servant 
In contrast to name, this crone is twisted, veeery Evil version of Nanny Ogg. She seems friendly and caring, but it quickly changes into cynical condescension and snooping – she will pretend that her guests are her small grandchildren and will ask them about everything, especially private live. She will, for example, say to Illithid (one of PCs): “My dear, aren't your clothes too warm? Yuo don't look good! Your skin is as pink and unhealthy as that of me, your over-100 years old granny!” 
And a small, but IMHO funny detail: in her hut there's a painting picturing A'kin and Shemmy as a pair – and she swears that she was at their wedding I'm looking mostly for any other funny texts she could say to anyone.
*This word is “Weatherwax” translated to Polish and stylized into Russian surname. Previously it was "Pogodowosk" - thanks to Hyaenadon for suggesting me more Russian version
Sisyphus: One day the most famous convivted for hard labour person in the Multiverse realised that he had succesfully rolled his boulder to the top of his hill. Then, an arcanoloth appeared next to him and said something like: "You're free, mortal. But it ain't absolute freedom - you have to change identity and tell noone who are you".
That's the olny thing I have fixed about him to this time. How would You react if You were in his shoes? How do You see fallen gods' favorite's personality? I'd be especially thankful for Your concepts on this character.
PS. for some unknown reasons, I can't see my avatar (jpg. format, surely less than 10 KB). Does anybody know what's going on? Thanks in advance for help.
I might play Sisyphus a little different. He is an egomaniac who is exceedingly clever, and who was given his imprisonment as punishment for his hubris. This is a guy who tricks the gods on a number of occasions, and who fathers odysseus. In short, this guy must be a super genius by D&D standards. My suggestion would be that he escapes because he tricks someone or something into taking over the boulder rolling task for him. Because of his incredible genius and insane ambition, he is a threat to the planes. His plan is nothing less than to avenge himself of Zeus' slight by using Zeus' passions against him. Through an elaborate series of schemes (insert plot hooks here) he intends to eventually lure Zeus into carceri, and a permanent prison composed of some powerful restricting artifact (which he also gained through some trickery or other, perhaps tricking Tartarus out of his Chains for the second time, which should be amusing to any greek mythology buffs). Once he imprisons Zeus, he will claim Zeus' throne for himself and ascend to Godhood on mount olympus. It is up to the PCs to make sure this doesn't happen (or does happen, depending upon their inclinations).