Exalted campaign:
The PCs are all people from modern-day Earth who Exalted as Solars for a number of convoluted but perfectly plausible reasons, and then were subsequently abducted to Creation by a Gold Faction Sidereal who conveniently died a Heroic Death before he could answer any of their questions.
They then emerged in An-Teng, a subject nation of the Scarlet Empire (the most powerful nation of this world and whose rulers prefer to kill Solars on sight), and learned just enough about this strange new world to get into trouble.
Now they have made a bet with a Lunar Warlord that they could "liberate" An-Teng from the rule of the Scarlet Empire within one year, or else the Lunar gets to try his approach, which would lead to considerably more bloodshed than the PCs are willing to tolerate.
So far, they have done well - only two weeks have passed, and they are basically running the bureaucracy of one of the larger cities. But from now on, things will get interesting, as they will run into the flunkies of the First and Forsaken Lion, the most powerful Deathlord of them all - not to mention the Wyld Hunt and scores of Dragon-Blooded if they show off in front of the wrong people. And then there is a Fair Folk noble who is just dying to get a reaction out of them after one of them defeated him in a duel, Gold Faction members who will try to recruit them into the Cult of the Illuminated once they learn of them, and whatever else can think of.
And if they should figure out a way of returning back home to Earth, then that's when I will spring the really nasty surprises on them...
GURPS Eberron:
The PCs are a bunch of your typical adventuring never-do-wells who got lucky twice - first, they got shipwrecked on a remote island where they became the "leaders" of a tribe of pureblood yuan-tis by slaughtering their halfblood and abomination leaders (actually, the purebloods think they are useful figureheads - the PCs haven't realized that the yuan-ti are all smarter than all but one of the PCs...).
Then they found an abandoned prototype Creation Forge on the next island they settled on with their new tribe - there were only a few components missing to reactivate it, which they are now trying to gather. Soon, they hope to be able to create their very own Warforged Army. But of course, things rarely go as smoothly as you would expect...