Holy crap. And I thought I was the only one.
I've had really long strands of unexplainable thoughts...never thought anyone else had experienced it but me.
When I go to sleep, I feel like my arms are vibrating or not where they are, too. I think it's not too rare.
When I try and clear my head, I get semi-coherent half-formed thoughts going through my head. They're usually not very developed, though, and I just forget about them.