a few come to mind, this wasnt so stupid on my part, but my brother gave me a A.A spinebuster on our kitchen floor in a "hardcore match" and i layed there for about 20 mins.
we also had another match going on and i was trying to be like the great muta and ran and jumped off the trampoline but he moved and didnt catch me so i sprained my ankle and busted up my knee's.
in college i lost a bet to my friend about a smackdown taping so he got to macho man elbow me from the top of his porch (about 7 feet from the grass where i was laying). he nailed it perfectly (perfect form too) and then my friend jason volunteer'd and my other friend was off a little and came down on his face. thank goodness jason put his hands up.
the 3 of us also had a impromtu handicap match in the dorms where we fought in our rooms,in the hallways,down in the bathroom and spilled over into our R.A's room. but that wasnt stupid,that was just awesome