chumbucket I know these so well. I had both legs do this after my last marathon. I recall screaming like a banshee.
Anaxagoras When I had this happen to me, I thought it was the worst pain imaginable. A couple years later, I had it happen to my hamstrings. Turns out I was wrong... but I don't want to declare the hamstring cramps the worst imaginable for fear that life will see fit to prove me wrong again.