OT: A most peculiar thing...

[capnq]

See a doctor IMMEDIATELY. All of those symptoms are consistent with a minor stroke.

[Randallw]

Not to lighten the tone of what appears to be a serious discussion, but several months ago I had a weird experience. I was lying in bed half asleep when I noticed that although I was fairly rigid my left arm and leg were spasming. I was holding them back but they felt like they wanted to jump about. I might even have had to lie on my arm to keep it still. I haven't felt it since then though.