Core Wars

Core Wars is a computer core simulation game, in which the objective is for a program to take over the core. The game works by having programs run inside a simulated code, such as pMARS, the game ends after X number of moves, or until a program controls the entire code. The programs are created in a fake assembly language called redcode.

Online contests are held in which people submit their programs that will compete. Various web sites host these arenas, and you can find a very good number of competing programs still on them.