Think back to your childhood school days. Remember recess, with the jungle gym, swings, four square and all the other games. It seems one of the ol’ grade school games is becoming popular among adults now. Leagues are forming all over the country, there’s a national association for it, and there’s even a movie coming out this summer about this game. Take a guess on what you think it is before you check out the article.

CNN.com - Adults find exercise in an old playground favorite