I am encouraged that other people experience these vibrations! Yay, I'm not crazy!! Mine happen only occasionally ...always just as I am starting to fall asleep and don't last for more than 5 minutes at any given time...full body including legs. Last night was the first time I experienced them while falling asleep on my couch watching tv...it wasn't a planned nap I just suddenly got really tired and as I was drifting off I thought the house was shaking...then realized it was a slightly more severe version of the body vibrations. I did fall asleep in spite of them. I haven't been able to relate them to any food/beverage/activity prior to the occurrence...they just come seemingly at random. I would love to know the cause!