It's the next big thing, and I've jumped onto this bandwagon.
My intention is to write a set of game objects that can be dropped into a game, and then let them do the rest themselves, by reacting to the player and each other.
I've also been influenced by a video of Quake 4, where the player walked around the landscape and a large ship swooped down from the sky. So an additional aim is to have an environment that the player can walk around while cool stuff happens around them.
You can download my current effort at SourceForge. It's called Emergent Mercenary, and is currently very alpha, though you can walk around.