Meet the Steppie Balance Board: a cool accessory for standing desks that lets you have more fun while working. It relies on low-impact movement to engage stabilizing muscles of your back, core, hips, and legs. It rocks back and forth while strengthening your muscles.
The above video shows the Steppie Board in action. The device can help you improve your posture and achieve increased circulation and better joint mobility. Sets you back under $100.