I noticed my 6 month old, Chaz, investigating the bathtub many times, so I decided to take one of our many ping pong balls, roll it and bounce it around in the tub . . . he was facsinated and loved it! We have a fiberglass tub/shower so the ball really gets to rocking and rolling all over the place! Great game for the hyperactive kitty that usually exhausts you. Once they get the swatting idea, you are free to go and leave them while the ball does the entertaining!