Zorb Ball - Giant Inflatable Human Hamster Ball With One Entrance. Once inside, you can walk or run to roll the ball forward. Think of it as a giant hamster ball, where the person inside is the hamster. Now this may not seem all that exciting, but throw in another sphere and perhaps some obstacles and you have got yourself a race. Re-enact scenes from the popular television game show, “American Gladiators,” and embrace your competitive spirit.