Heheh, NCES is so close to NCIS...
The idea:
The player characters are well known - famous even, and have for a long time been doing incredible deeds around the planes. At level 20, after all, there is little that you can't do. As such, Belial had no trouble finding out about them, and asking for their audience, to make an offer.
The deal was simple: he had a legion of devils ready to unleash in one of his usual incursions, something that would strongly affect *a* plane and cause much suffering. If the team agreed to help him, the devils would instead be sent to the Blood War, where they would probably die senseless deaths or, failing that, would achieve victories against demons - equal in evil. He also offered magical items and prestige/favours, and all they must do is first prove themselves in the testing grounds (a series of fiendish challenges), and then deal with his errant devil daughter, Fierna.
Of course, it's altogether possible that Fierna could have plans of her own - even to hire the party herself...
The system:
Dungeons and Dragons 3.X (it makes little difference)
The specifics:
Starting level is 20, using 32 point buy for ability scores.
Just about every book and supplement is allowed - check with me first. I will stab you in the face though if you want to be psionic or a warforged.
If you want to be a weird race, talk to me and we'll work out a fair way to play one rather than the retarded Savage Species rules.
I'll be setting some ballpark areas for the various numbers. I want the players to have their AC, to hit bonus etc. in those areas so that we don't end up with "One player can't hit this monster, another can't miss it".
I allow and encourage use of Gaming Den/Frank&K material.
The game will go into low Epic levels. Instead of using the normal Epic rules, I will simply say this: tell me the basic idea of what you want the character to be doing ("A grand wizard who shapes the planes!", "a thief who steals souls, minds and even loyalties", "a knight who rides a friggin dragon") and I'll make a way for you to progress and do that.
Finally, loot: you can have anything that costs 15K or less, and as many as you want. If it costs even a penny more, it's special. You may each have:
1 item worth up to 200,000 GP
2 items worth up to 100,000 GP each
5 items worth up to 50,000 GP each
10 items worth up to 20,000 GP each
Sexiness:
Some of the tasks will involve sexual elements. Have fun with it. You can use stuff from the various "Sex in D&D" sources, but we're not using the "Have sex with people" skill, nor the Appearance stat. So if you like a Book of Erotic Fantasy item, class or feat, you can use it, but taking ranks in Perform: in the bedroom is a waste of skill points. Feel free to make up your own silly ideas for feats and stuff related to kinks and things (and using them in combat) and run them by me - I once made an entire supplement all about spanking in D&D, complete with feats, spells, prestige classes, magic items, monsters and ToB manoeuvres.