In 1990, David Harris created a free programming game called Robowar, where people wrote small AI programs that duelled each other to the death in an arena.
Over the years, its popularity grew, and more and more advanced programs were being written in Robowar's simple language - Robotalk. Unfortunately, it died in the late 90s and early 2000s, but appears to have risen again with the release of a Windows version.
If you think you're a good AI programmer, then download Robowar and some bots (Try finding Tournament 24 bots and Tournament 23 bots - the latter has all of my bots in it).
Download RobowarFind all bots hereI doubt people will be interested and would prefer to play pre-programmed games, but meh.