Hard rubber balls, with LED centers that light up and go blinkety when they whack into something solid after they're thrown.
Hardcore Mac Hall fans will know where this is leading.
Australian Indoor-Rules Quidditch!
Now I just need a team, a field, and some "broomsticks"... I wonder if anyone at work would be up for a game after-hours? Probably Cute Geek Super and the usual suspects. I should share the comic with them.