There's an old trick where you take an open race ball bearing, and direct a blast of compressed air at the ball race while holding it by the inner shell. The outer bearing shell will spin twice as fast as you can make the race spin with the compressed air, so it's really moving. Then you put the spinning bearing on the floor, and watch it race toward the wall. It hits the wall, bounces up and back, hits the floor, races back to the wall since it's still spinning like mad, etc. until it runs out of energy or goes off course. Tons of fun for the bored.