I found this nice little game called NERO (Neuro-Evolving Robotic Operatives), by accident by the way.
http://www.nerogame.org/
It is built on the Torque game engine and has a REALLY nice AI. The idea is basically to train robots to fight. In the start they are like little babies or puppies, they can't do a thing. They just run around doing random stuff and by rewarding or punishing them you can train them for a certain task. The AI is just amazing, the robots really learn things.
