I think this all the time. Try going in pitch black with a picher of water, a flashlight, and a bowl. As you pour the water in to the bowl shine the flashlight across the water. It will move sightly with the light.
THIS COMIC IS BASED ON TRUE EVENTS. What's really funny is that to this day, I can't sleep, even lie down or sit & read in a room if the closet door is open, even a smidge. My Hubby finds it very amusing :)