I can thing of two; first was when I was over at a friend's house, two guys, and one was wearing shorts, and i'm guessing, went commando. The angle at which he was sitting meant that part of his man bits had popped out, and it wasn't pretty. UGH.
Second was when my former manager at my former PT job broke her leg, and we went to visit her. She broke it badly, and as such, as one of those external hardware things on it. Now, I can watch brain surgery, open heart surgery, surgery where you cut someone open, nad pull out their organs etc. i am a trauma show junkie. But what I can't stand is anything orthopedic. it just grosses me out. So when she pulled back the blanket, to reveal this thing on her leg, with pins going into it, i almost gagged and had to look away.