Let's hear 'em. I know we've done this before, but there are enough new people around that I hope we can get some good new stories.
Here's one of my favorites from when I lived in Charleston (which is said to be one of the most haunted cities in America). My roommate and I were living in a two hundred year old house. Our apartment was essentially the ballroom of the house with a kitchen added on in the back. We used to hear footsteps starting at the top of the staircase outside our door go tearing down through the house, then the front door would open and slam shut. No one was ever out there. Also there were often strange shadows on the walls that we couldn't explain. We didn't live there very long, thank goodness!