A long time ago I was riding in a subway train. The subway car was mostly or very likely completely empty because it was late at night, likely the last one of the day. There was a paper clip laying on the floor between my feet and then I noticed that it had started to stand up on its own. One of the ends of the paperclip was still touching the floor inside the train, but the other end was pointed up and it wobbled around softly for a while.

A day or two later I mentioned this to my electricity teacher at the time, an electrical engineer who just happened to work for the subway agency. I expected him to say that it was some kind of magnetic effect due to the proximity of the high-voltage supply lines used to power the subway, but he instead said that it was impossible and I must have been hallucinating. I've never hallucinated in my life. I still wonder what could have caused that phenomenon. I'm sure that there's a scientific explanation for it, but I haven't found it yet.