Oh and one or two avatars can play with it.
The ball comes with four "seats", two are for the players one directly under the ball and one a distance away. Select the one under the ball to play keep-up, or put someone on both spots to volley it back and forth.
The remaining two places are "reset" spots, when you've finished playing stand on one of the reset spots to stop the animation.
This is like my other product "Play with the beach ball" only the ball is twice the size, moves slower, and squashes slightly when it bounces. I slowed it down because the animation seemed too manic otherwise.