Formerly known as one wall handball, the name was changed to prevent the confusion between wallball and team handball. It is the oldest game there is - just need a wall and a ball.
Players can play singles or doubles. Players hit the ball against the wall, and the opposing player can let the ball bounce only once, or can it the ball in the air, and must return it to the wall. Both players must hit the ball to the wall and its bounce must stay within the boundaries of the court. Player use both hands to hit the ball. It is extremely easy to learn, and takes a lifetime to master. It is very good cardio workout and develops athletic literacy, hand eye coordination in both hands, developed more speed and better footwork, all of which can help in all sports. It is a great sport itself, and a great cross training activity for other sports.