I have three rather creepy ones. First off during 6th Form we were watching the movie Kes in Film Studies. One of the film's scenes involved the boy, Billy, being forced to shower in cold water after a PE lesson after everyone else. The PE teacher makes him strip off and go in and instructs the other boys in the class to not allow him out, the scene ending with Billy climbing naked over the shower walls to escape.
Our teacher then proceeded to tell us how he suffered a familiar situation as a kid. Apparently while at school something happened during a PE match, I don't remember exactly what, he might have forgotten his kit or gotten hurt during a game, something along those lines. His PE teacher brought him in, took him to the little office near the changing rooms and made him strip down completely naked in front of him. Again I've no idea what the exact context was to it, he said there was no reason the teacher made him do this, but it scared and embarrassed him senseless, I don't blame him one bit.
The second story is far more gruesome. My english teacher during Secondary School often told us stories from his childhood, I liked him alot. In fact both him and my Film Studies teacher were my favourites during Secondary School and 6th Form.
He told us when he was a boy he and the other kids would play cowboys and indians at a local mine/quarry. There was a big pile of scrap, rubble, slag and stuff. Basically a big mound that kids love to play around on. Above this pile was a sort of mine cart that ran along a suspended rail. This bucket/cart would carry stuff from the mines/quarry and dump it on the pile, then carry on and disappear into a mining tunnel. One day when my teacher was playing with his friends there, as usual, when one of the boys naturally wanted to climb into the cart and have a short ride. What kid wouldn't? He went to the top of the pile, and sure enough managed to climb in the cart as it passed over. He didn't jump out though, he continued to sit in it as it went along into the tunnel. According to my teacher, the boy was dumped out into a rock crushing machine inside the mine, and was completely mashed up and killed horribly. Yeah.... Other stories he told included running over caterpillars on his bicycles, his grandmother throwing a firework into their fireplace and blowing up in her face (she wasn't hurt, just shocked).
Finally, another teacher told us a story when he was younger. Whilst on an average day in the neighbourhood, he saw a little kid playing by the road. The kid crouched down to look at or pick something up, to which his head was immediately crushed by a reversing vehicle. Jesus I had some weird stories told by my teachers, even my old Music teacher told us how a cat was run over and sprayed blood all over his car, he didn't have time to clean it as he was on his way to an important meeting that day. Anyway, we're getting on to four stories, and pretty grim ones at that =/