Calf raises can be done wherever there is a raised surface, such as a stairway. If you need balance, hold onto the railing. Facing the stairs, stand with only your toes on the stair and your feet extending out past it. Standing straight up, lower your body down below the level of the stair and then back up onto your toes.
Even though it seems as if this is an ankle exercise, it also works out your calf muscles.
The biggest emphasis on this exercise is the ability to go from an extreme negative position with ankle below toes to an extreme positive position, ankle fully raised.