If you build a pair of Jitterbugs, you can bet on them: Draw a circle on the table, shine a bright light on the circle, and wager on who escapes first or who stays in longest. If you prefer games of skill to those of chance, dig up a couple of cheap laser pointers, dim the lights, and see who can get their bug to escape the circle first by training the tiny prick of light on the maddeningly small photoresistor surface.