Play basketball on your iPhone. First practice and then try to hit as often as possible with 20 shots or with a limited number of attempts per hit.
How to play: Tap and hold the ball and drag the finger into the direction you want to shoot. The length determines the speed of the shot. Release the finger to shoot. The ball bounces realisticly from walls and the hoop. So you can even do trick shots.
Adjust the difficulty by adding a ceiling, fixing the basket and changing the gravity.