I've gotten massive cramps a few times, but once I was actually knocked off my bike a huge cramp in the hams (I had been stupidly ignoring the warning signs). People thought I was having a heart attack and despite my protests that I was fine, some well meaning person called 911 even though I specifically asked them not to. The cops really wanted me to accept an ambulance ride and only after waiting at least 20 minutes would they even agree to let me walk out of their sight.

The funniest cramp I ever got was while I was sleeping next to a large dog. Again, it was in the hams. When I seized up and yelled in the middle of the night, the dog thought it was under attack and chewed me up pretty good. I still have scars from that -- there is a reason why they say "let sleeping dogs lie"...