Several here in the office sit on big bouncy balls instead of office chairs. Purported to improve posture and exercise your core, it does look as though the evidence is slight. That said our 3 ball-sitters find they do pay more attention to sitting up straight, certainly a benefit. And sometimes the balls are used to get a good stretch in, another benefit. I find it a bit amusing when I look up and someone is bouncing away at their desk. Sometimes that music while on hold on the phone or waiting for the webinar to start gets them dancing/bouncing in their seats! The balls aren’t entirely without challenges. One is you can’t easily adjust their height which may impact the ergonomics of the rest of your office set up. While I wouldn’t advise this we do have one person who situates her ball on top of a large box to get added height. And please be careful reaching for something far off to the side of your desk! We’ve had a few near falls. No one’s fallen off their exercise ball yet, let’s hope no one ever does.