Mirror balls might have been cool back in the 1970s, but these days people crave something more exciting to spice up their efforts at throwing a party. This laser light ball built into an ordinary tennis ball should do the trick, potentially letting you blind up to 14 of your party guests at one shot.
Creator Matthew Leone took 14 red laser diodes, and somehow found a way to stuff them all inside a tennis ball along with Teensy micro-controller and a rechargeable battery. He even included a remote sensor that lets him change the light patterns from a distance to fit the mood.
Leone likes to call his creation a "cat toy for humans," but I tend to think of it as being a way cooler cousin of those lame disco balls the DJ would switch on during the slow dances.
It would be great if some company made a a ball like this that you could simply buy, but I suppose they'd be worried about lawsuits with all of those laser beams jumping around. If you're feeling handy and want to make your own, Matthew has provided full instructions on the Instructables site linked below. Or you can just follow the video.