Wobble board balance is a great exercise for general ankle, knee, hip and core stability as well as specific rehabilitation following injuries such as a sprained ankle.
Bosu ball squats
Bosu ball squats are a great all body exercise to work your core as well as strengthen your hips, knees and ankles.
Resisted Shoulder Rotation
This is a great exercise for early stage shoulder stability to improve your rotator cuff strength.