I threw together a little Java Game (well, precursor to a game, anyway), in a GUI class a couple of years ago. It looked like this: It takes an input file describing a map in grid form, and populates it with little independently threaded robot characters. I never actually implemented any AI, so they just run around randomly bumping into obstacles. The map file can also include "treasures", which the 'bots then run around and occasionally stumble across by dumb luck. The program keeps score for them. I was being very responsible about OOD when I wrote this, so it's pretty extensible and provides a great framework for writing little bots ... I just never bothered to do anything more with it.