Single leg stance, bouncing a ball against a wall (Balance, single-leg, throwing/catching ball against wall)

Stand up straight in front of a solid wall holding a ball.
Stand on your weakest leg and get your balance, ensuring you do not rest your elevated leg against the stance leg.
Bounce a medium sized ball against the wall, hard enough so you can catch it.
If this is difficult to do with both arms, then use your strongest arm.
Try changing the direction of your throw, so you have to lean to catch it.