If you come to my office in a few months, perhaps you will have to sit on a different type of chair. Apparently, some office workers are thinking of new ways to improve their health. One way is to replace the standard chair with a large, exercise ball as the thing to sit on all day. I am sure it helps. If anything, this chair keeps you awake.
Balaam's Ass 
These would be great, until someone falls off and sues because their boss wouldn’t provide a proper fully adjustable ergonimicaly designed chair.