1. Roll your ankles regularly. As with your wrists, roll the ankles in a clockwise motion 3 times, then counterclockwise. This helps improve blood circulation, and prevents that tingling feeling you can get when blood circulation is cut off.
2. Toe raises. Lift your toes while keeping your heels firmly on the ground. While you can do this exercise standing, it works very well while seated.
3. While sitting in your chair, extend your right leg until it is level with your hip. Hold as long as you are comfortable and then relax it. Alternate sides.