Leg cramps

Leg cramps. Who invented them and what are they good for?

I find myself bouncing out of bed at 3 or 4am because my calf has seized up in such a way that I cannot move my foot, not even using my hands to pull, and the only way to fix it is to get up and stand on it.

Very painful. My calf is sore all day after one of these.

I also get cramps in my feet, which aren't quite so painful, and in my hip. The hip only happens if I lie on my back. All the books say you shouldn't lie on your back anyway after week 16, but I have no control over how I end up whilst asleep. And once the pain in my hip wakes me up it's too late. The hip is a tricky one, hard to find a position that'll pull the muscle out of spasm. Very unpleasant too, I can feel my whole leg down to the foot twist involuntarily.

And the Blob is happily bouncing around, unaware of my troubles...