I don't know what they do in your neck of the woods, but here in the glorious SF Bay Area, there's been a serious resurgence of kid games for grown-ups. And kids, but we definitely get the adults involved. There's been large-scale pillow fights and kickball leagues and organized tag and so on. I think many of the trends start in far-off places like Oregon and New York, but here we have the right combination of mild weather year-round and earnestness and web-savvy people and geeks (hi!) to take these competitions to the next level.
This weekend was my favorite so far: the Cardboard Tube Fighting Championship. Little did I know that my and my sister's epic battles with those empty wrapping paper tubes would prove to be excellent training for an actual tournament, though we never thought to make cardboard armor. The rules included no stabbing or goring, no defending with anything other than cardboard, and no face blows. As far as I know, no one was beheaded or hospitalized, but there's always next time. And if you can't get behind cardboard tube battles, you are dead inside.
I'm thinking of starting a hopscotch league, if anyone is interested.