Physically move around to play your sport! Only boxing and tennis so far, but more will be added. Note: You should have some open space! Tennis is first to 17, and in boxing, the player who has no health left wins. This is designed for people to stand a foot or so away from their screen.
Credit to Wii for the idea, VectorStock for the boxing ring, and me for everything else! It's the only Wii Sports with physical moving!