Question: Do have any specific exercise for cramp in the calves?
You can try this simple exercise by standing up straight on your tippy-toes and hold it for as long as you can manage. This will stretch the calf muscles and reduce the spasm. Take a break every few seconds and then continue stretching.
You can also check this link from EFI website for some calf stretches: http://exercisesforinjuries.com/?s=calf&x=0&y=0
If you suspect, any swelling and obvious deformity in your calves then it is best to seek for further medical intervention.
I hope this has helped you!