So I'm at the gym yesterday and doing my own squats when this girl comes up next to me and gets one of those half stability balls(usually I see people doing push-ups on them), like the regular huge ball things, but cut in half and flat on one side. She puts it on the ground with the flat side up, then grabs a barbell and gets on top and does squats while standing on it! I've never seen anything like that before. I was pretty impressed I must say. She was pretty shaky, to the point that I waited to do my squats because I didn't want her to crash into me. But she held it together. I can imagine standing on one of those, but NOT doing squats at the same time. Not that I'll be trying those anytime soon!