The clever folks at Nerf have come out with a set of sports equipment (Firevision Football and Firevision Hyper Bounce Ball) that allows for game play at night. The ball has, what Nerf calls, Microprism Technology. For you and me, that means that the balls have a some very reflective inserts and the users have glasses with lights on them. When the ball gets within 100-feet from the person wearing the glasses it starts to reflect light back, making the ball look like it is glowing.
Video of some people playing catch in the dark after the break.