I don't generally tell people this, because I'm still picking at it (Being a rationalist, I accept the supernatural as a possibility, but am still interested in some other possibility as well).

It was years ago in Edinburgh's famed Vaults, I was trailing the group because... well, because that's where I was. What other people thought happened: I tripped and went sideways into the wall (Not at all difficult to imagine, the Vaults aren't exactly handicap friendly). And I'm sure that's what it would have looked like if anyone was watching, but I distinctly felt shoved, forcefully enough that my head it the wall as well as my shoulder. I'm light enough of my feet that I recovered enough not to be anything more than irritated, but the expected fellow student was not there. The nearest person was just turning around to see what had happened and was five feet away.

I swear I heard laughter, but that could easily have been someone in the group laughing at something else (and likely was). But I was most certainly affected by something outside myself and gravity. I still don't believe in that which cannot be scientifically verified, but the facts are as presented. That was the most unusual thing that has ever happened to me in terms of the unexplainable.