This activity is for young players to help them control both racquet and contact with ball. You will need at least three players. Two players face each other a few feet apart. A third player stands between them with feet apart. The two players pass a ball to each other along the ground. The ball must pass through the legs of the third player. If the ball touches the middle player or does not go between their legs, the player who missed is now in the middle.
I find my young players delighted when I add the option to make a ridiculous and obnoxious sound effect when the ball misses. :)