The interesting thread on teacups reminded me of my own unexplained mystery. And, it makes me think how many people will immediately think of ghosts or gods when something strange happens, instead of finding out what is really going on. There could be a whole category for such stories! Anyway, I had just moved into a rental house. There was a scrap of carpet matching the stuff on most of the floor, that was apparently meant to go in front of the fireplace for extra protection against dropping burning logs or whatever. Without anyone else in the house yet, not even pets, I found that this piece of rug would move on its own. After some hours, it was seen to have shifted position. Furthermore, it creeped with enough force to bunch itself up when it ran into the couch, forming huge folds. Any clue what causes this?