Ok, I've had this idea for a while, but I'm not sure how this will work. I'll throw it up anyway.
Picture one of those 'galactic arena' thingies, where the greatest heroes are there to fight to the death. That's where our heroes are, gathered from all around the uni/multi-verse
Except that they're not there to fight to the death. Instead, the 'ruler' will give each one a card/dice number/something probability related. These will be totally random, and each item will represent a 'dungeon' or some other form of challenge.
This is where the fun comes. Perhaps a card can represent a 'creativity challenge'. The most descriptive post possible, or to blurt out a fact about themselves (the characters i mean). This will not only develop character, but if the questions are worded right, it's possible to get a lot of tension going on.
Another card could be a typical 'dungeon crawler'. A short scenario where the hero must go on and kill stuff/pass the test/become the next god in that small world. Your typical BB sorta dungeon or battle.
And I say allow the characters to die. But also implement a mechanism where it doesn't punish the player. Perhaps 'revive' the character back at the arena with no penalty (or minimum penalty), or get a clone or something. If the player wants, they can just create a new character and restart.
Now I see a lot of problems with this. BB master must post like crazy, especially with so many characters. This may mean that everything is reduced to a 'creativity challenge', which is cool, but a bit one sided. There's also the problem of motivation. I'm not sure how a 'plot' can be formulated to drive the board itself.
But if someone can fix these things, I think it'll be quite fun, with all the diversity.
@Chorus: I prefer Dragonlance myself, but Drizzt's awesome all the same