I've posted this a couple of times before, but this thread seems appropriate for it
My wife and I woke up in the middle of the night to find all our lights out in the house. We had not lost power. The living room light that we always leave on overnight had been turned off. The bathroom night light was removed and placed under the sink. The computer had been unplugged, and the monitor cord was unplugged and neatly folded on the desk. All of the doors and windows in the house were unlocked, undamaged, and standing wide open. Our bedroom door was open, and the TV we always fall asleep to was turned off. Nothing was taken.
Our cats were both hiding behind the refrigerator and stayed there for most of the next day. Whenever someone came and knocked at the door, our larger cat would start to growl and stare at the door from then on. She no longer does this after we moved. We had a couple of other mildly strange things that happened in context with that apartment as well.