What are you playing right now, guys?
Nope. Follow the link for a description.
GGP bots are designed to be able to play different games, all with the same engine (same source code). It can play tic-tac-toe, checkers, chess...
The server gives the rules of the game at runtime, the bot processes the rules and figures out how to play it at runtime. And then it plays it against other GGP bots.