From August 2005 to late Spring 2006, I lived in an spacious old flat in Madison with 3 friends. One day I was home alone putting dishes away in the kitchen when I heard the loud sigh of a woman behind me. I hadn't heard anyone come in, but I wasn't startled because it sounded exactly like my housemate's girlfriend Joelle (whom I've known for years), and it was common for her to be there during the day. But when I turned around, she wasn't there. I checked the rest of the house but I was alone and the front door locked.
On another weekend, I was out of town with my fiancee visiting her family. All the rest of my housemates spent the weekend out of town as well (in fact one of them was out of state) except Tom, who stayed there with his girlfriend (the same previously mentioned Joelle). When I returned late Sunday night, Tom asked me where I had been all day, and I explained that I'd been out of town since Friday afternoon. Tom seemed a little alarmed by that, saying "We both saw you walk from your room to the kitchen and back at night yesterday while we were watching TV. It was dark, but we were sure it was you..." We were both a bit creeped out by the thought.
When I was alone in the computer room or my bedroom, I would frequently hear heavy footsteps creaking on the wood floor in the dining room. Eric Jon (one of the housemates) wore heavy, hard-soled boots indoors all the time, so I usually assumed it was just him until I went to welcome him home and discovered the flat was empty and I was alone. All three of the other housemates agreed that they had experienced this same phenomenon, and often.
Most of the things that happened there mimicked the actions of the flat's occupants. I wonder if the house just "remembered" the things that happened in it and replayed them.