Core Wars

n. A game between `assembler' programs in a simulated machine, where the objective is to kill your opponent's program by overwriting it. Popularized by A. K. Dewdney's column in `Scientific American' magazine, this was actually devised by Victor Vyssotsky, Robert Morris, and Dennis Ritchie in the early 1960s (their original game was called `Darwin' and ran on a PDP-1 at Bell Labs). See core.