Since this thread has a supernatural theme, I'll give you guys my dads experience.
The whole family is on a camping trip (we went almost every weekend in the summer) but my dad had work that weekend so he stayed home. He was watching a scary movie late at night.
He's sitting there and he hears a loud FWAP FWAP FWAP FWAP FWAP coming from the kitchen, behind the living room, seperated by an archway. Freaks him the fuck out. Jumps out of his chair and looks, nothing. Kitchen is emtpy.
He sits back down and a few seconds later there it is again! It's loud and sudden, and as soon as he looks again it stops. Happened again a third time, and this time he decides to stay for a bit and watch.
It was a fucking oscillating fan and a phone book.