Our son has loved those things since he was barely big enough to make one go. He outgrew the ones he had here. One day I felt sorry for him trying to bounce on that little ball so I went searching and found that site. I got him one of the bigger balls and he LOVES it.
He bounces all over the house. He'll need something from his room, grab his ball and bounce all the way back to his bedroom. He often just sits on it in front of the TV.
Those are not cheap, but they are good quality and hold up really well.
I loved those when I was a kid! My brothers and I would have races on them. And on Saturday mornings we'd sit on them while watching cartoons and eating cereal. We'd also use them to help add more space to our blanket tents that we'd make in the living room.
Ya know, we might have just solved the problem about energy efficient cars. Everybody could just buy one of these to use for transportation. I'm sure someone could come up with a little cart that attaches somehow to transport groceries, etc. But we'd have to keep an eye on JD....he'd be the first one to smack someone when he's stuck in bouncy ball traffic on his way to or from work.