Wow, I had the coolest idea for a ghost story last night. Have you ever heard your house creaking and almost sounding like it's breathing late at night? I was thinking about a guy who built his house to incorporate nanite repair bots because he was afraid of storm damage. Then he dies (perhaps the sound of the nanites working at night drove him nuts?) and the house is sold, knocked down, and a new house is built by the new family. Everything is fine until they start hearing noises at night, and the house is gradually changed back into the old house. I don't know about you, but having things changed back into the house of a madman who killed himself would freak me out.