Last year, my totally sane, non-drinking daughter was sitting in her living room and there was a chrome dog dish in the middle of the room. It suddenly flipped over. Nothing was around that could've done it!
So her sister was making fun of her about it and this year, the sister and her kids were in the bathroom, door shut, drying off the dog. They heard a crash and ran out in the living room. One of the lamps was in the middle of the living room, smashed.
They were locked in the house; no one else was anywhere around.