I got a few, but the one i can recall the easiest was when I was about 8 or 9 years old.
I was inside of my bedroom playing with a set of wooden trains I had. My grandmother, mother, and father were the only other people in the house, and they were outside at the time. As I'm playing, I idly look up at my door, for no reason other than to look. Suddenly, at that moment, the knob turned (it's one of those longer knobs that fits in a fist) all the way to its lowest position, and the door swung open until it nearly hit the wall. The knob was still down in it's lowest position. No one was in the doorway.
After a second or two of staring, the door swung completely closed again (which required some force, since the door had a stopper) and then the handle returned to its normal position. For some reason, I kept completely level and went on playing. That experience still is a lingering question in my mind.
EDIT: Spacethingy, I know the feeling, it's happen to me before as well.