The cool thing was that I forgot to write the bounds check to make sure the ant stayed inside the framebuffer! So the ant would happily trundle off-screen, encounter arbitrary bits that were in that memory, and would often eventually return back on the screen from a different location. Or sometimes (probably due to encountering zeros offscreen) it would run a lap around the edge of the screen and then veer back inward.
Langton's Ant: http://en.wikipedia.org/wiki/Langtons_ant
I still am a "kid", and it amuses me that I'm making the same stuff on modern platforms that have already been done on DOS machines by kids like me.