Me and a few friends were out camping and it was dark and we saw a big group of bats flying over towards the bush and one guy asks "I wonder why they all decided to fly over that direction." Then another friend says "Maybe your mom is over there." I was like for a few seconds and ask what the hell he is talking about and he goes: "Because everybody has had a bat over her" I could not stop laughing for minutes, I didn't even know if the joke made sense or not, if it does it works on so many levels. I just thought I'd share.
The joke itself isn't great (as with all 'that's what she said' jokes) What made me geek out was the lateral thinking.