Chess engines are fascinating to study for a lot of reasons. I've done a bit of tinkering with some of the open source programs available - check out Stockfish

Chess engines are fascinating to study for a lot of reasons. I've done a bit of tinkering with some of the open source programs available - check out Stockfish and Crafty for some very nice code to work with. If you dig into the computer chess scene, there has actually been a lot of heated drama about source code provenance of various proprietary and open programs like Rybka and the Ippolit family.