Peter (Pontypridd, Rhondda Cynon Taff) on 04/29/2013:

Point your toes to your nose as hard as you can, standing up or lying down all ways work.

Myself and my partner both sufferd with this for many years, total agony, I forget who told me this but it works every time instantly. I was swimming in the freazing cold sea once and got a leg cramp some way out, toes to nose and it went, if I had not known that then I don't think I'd be typing this now.

Oh, and no long lasting after pains :)