Andrew (8) has brought a game home from school. You try to get someone else to say "What?" then you say "You're stuck with it." Stupid third grade stuff, but we're all doing it now.
Usually, the strategy is to catch someone off-guard and call their name; unaware victims will just reply "What?" However, other strategies like mumbling, speaking in other languages (Andrew likes Huttese from Star Wars), and saying something non-sensical seem to work well too.
Michelle, not surprisingly, is the most devious and clever at this. Michael (5) doesn't quite get the rules and will just blurt out "you're stuck with it" and seemingly random occasions and then laugh and gloat (usually doing a little victory dance as well). We're all a little more cautious now, usually replying "Yes?" when our names are called.
In the JV version we play, the word "what" has to be said alone. I've seen Andrew's classmates play the varsity version where any usage of "what" results in getting slammed.
I have no idea where this silly game came from or why it's bad to "be stuck with it", but there you go. I have visions of calling Andrew when he's forty and getting him "stuck with it." I can't wait.