It is a game created in Minnesota by teenagers that played way to much Call of Duty: Black Ops. The point of this game is to hit the other team's player with a tennis ball. To be "out" the player must be hit twice by the other team. This game could be played in a big field, park or other area that would work. You can have free for all this is were every man fights for himself.
This one time I was playing with friends and I hit one of them in the face with a tennis ball. Also another time we had an all out war at the local park. We came up with Pick a rabbit's nose when we played Black Ops for four hours straight.