How old are you?
Hydrate better during and after exercise, take on electrolytes, don't drink alcohol. Might help
Are you sure its your calf not your achilles.
I often do some calf stretches just before going to bed in order to stop them mithering me after climbing..And just now I thought of this, and you..http://www.mobilitywod.com/2012/04/introducing-the-bone-saw-calf-smash-redux.html