Life

Well, Joe guessed correctly and first that the previously mentioned batch file is an implementation of Conway's Game of Life.

I wrote a slightly better implementation in C#, and it allows more than just 2 states, but it's not very sophisticated:

While I was writing that version, however, I stumbled across a much more advanced implementation (in the same way that the B-2 is more advanced than a kite), called Golly.

I highly recommend checking it out, but I should warn you that it might cause you to waste hours if not days staring at the blinkenlights.