A variation of dodgeball played with two mats, one on each side of the court, gym, etc. When players get out, they go to the mat (or prison) on the other side of the court. To get back in the game, they must catch a ball thrown from a teammate on the other side. The game continues until an entire team is in prison, making the opposing team the winner.
We lost the game of prisonball because we couldn't get anyone out of jail/prison.