This is a picture of the chair I made for my computer desk out of an old exercise ball of my wife's. It was one of those fad things she bought and stopped using after awhile. She's a sucker for fad exercise gear. This thing is though, it makes a very comfortable seat and since I needed a chair I commandeered the ball for my own use. Of course I had to build a little box for the ball to sit in so that it would A) be high enough to use (it compresses a heck of a lot when you sit on it) and B) stop rolling across the room whenever you get off it. The spikeys on the ball do a good job of making sure the cushion doesn't slip off it. Looks like I'm sitting on a giant purple sea urchin with a brown plaid beret.