As an x gymnast, my ankles are pretty shot... but one exercise we did to get them back after routine sprains were stairs.
VERY slow dips with you heels hanging off the edge. Do 10 on each stair, up the whole stair case. Each stair alternate with 1. feet pointing straight forward. 2. toes pointing inward. 3. toes pointing outward.
On the way down, hang your toes off the edge and dip them down and then back up as far as you can while keeping the weight on your heels. Do this 10 times per step, all the way down. Repeat every time you go up and down stairs.