working out at work (Page 2)

Instead of a full on stability ball, they do make these disc type things that sit on your chair that are supposed to work in the same way.  Here's an example I just googled:

http://naturalfitnessinc.com/index.php?main_page=product_info&cPath=3_1_7&products_id=16

Haven't tried it yet myself.  I use work time for BT surfing.