Lecture #3 looked at game playing, in particular search techniques which can be used by agents engaged in playing games against each other.
You may also be interested in reading up on some powerful game playing programs. Chinook, which plays Checkers, is described in:
Jonathan Schaeffer, Robert Lake, Paul Lu, Martin Bryant, Chinook: The World Man-Machine Checkers Champion, AI Magazine, 17(1), 21-29, 1996.You can find out about the Deep Blue chess playing program at the official IBM site. Finally, the Poker Research Group at the University of Alberta has one of the leading computer poker players.