Robocode is an Open Source educational game by Mathew Nelson (originally R was provided by IBM). It is designed to help people learn to program in Java and enjoy the experience. It is very easy to start - a simple robot can be written in just a few minutes - but perfecting a bot can take months or more. Competitors write software that controls a miniature tank that fights other identically-built (but differently programmed) tanks in a playing field. Robots move, shoot at each other, scan for each other, and hit the walls (or other robots) if they aren t careful. Though the idea of this game may seem simple, the actual strategy needed to win is not.
Good robots have hundreds of lines in their code dedicated to strategy. Some of the more successful robots use techniques such as statistical analysis and attempts at neural networks in their designs. One can test a robot against many other competitors by downloading their bytecode, so design competition is fierce. Robocode provides a security sandbox (bots are restricted in what they can do on the machine they run on) which makes this a safe thing to do.