Personal trainers use medicine balls to turn clients' flab into rock-hard abs, but can you imagine hefting a medicine ball over a volleyball net? That's exactly what players do during a game of Hooverball. This backyard variation on volleyball was once the No. 1 White House sport, thanks to President Herbert Hoover's love for the game. It was invented in 1928 by a White House physician to keep Hoover at his fighting weight.
If you'd like to reenact a rousing match of Hooverball in your backyard, you'll need a six-pound medicine ball, a few friends and a volleyball net. A player on each team, designated as the server, will throw the ball over the net. An opponent must catch and return the ball in one motion. The side that fails to catch the ball loses the point [source: Herbert Hoover Presidential Library Association].