Definitely won't be funny at all now, but the other day I was in the pub - went for a wee. As I walked through the door of the gents, I applied way too much pressure to the door to open it, and as a result the door smashed into the side of the wall.
When the door smashed into the wall a bloke that was standing at one of the urinals turned round and said "Fuck me, I thought it was the congressman walking in then..!"

I know that it doesn't make much sense, but it was funny at the time.