I saw a ufo once. I also feel like I've time slipped a few times. Woke up one morning and the clock said it was 8:30, then a few seconds later the clock said it was 7:59.
Not exactly, if the question refers specifically to aliens and other kinds of sci-fi paranormal things, rather than "the supernatural." (That is to say, aliens rather than ghosts, for example.) As for the latter, I've documented those on the "scariest thing that has ever happened to you" thread in this category ("Paranormal"). I've never seen a UFO, but my uncle swears that he saw one right in front of him that hovered over the lawn. As I am not the person to whom the incident occurred, I cannot vouch for its veracity, but I know he was quite serious about it.
I once had a strange circumstance a few weeks ago with my (analog) wristwatch, which worked perfectly fine until one day, in the middle of the afternoon, when I noticed that it was an hour behind the actual time. I first chocked it off to Daylight Savings until I realized that Daylight Savings didn't occur until Mar. 12 (yesterday). I don't really have an answer for it, except maybe that the watch's batteries are running low and that that caused it to be off. Funny thing about that, though, is that the watch operated fine that morning and hasn't lost any time since. Nothing paranormal per se, but interesting all the same.
The season come again for winter’s tales, I tell you one which my nurse told to me As watched I warily the swirling snows. “I’ll raise one up,” she swore, “of ghosts by night…”