thanks for your responses, guys. Bobby Coke, I think I have most of the ones you were going to mention because it was you who mentioned a lot of them in other threads on the subject, if I recall.

There's another one that I forgot to mention that I saw on Youtube once. It was from a British variety show and featured two detectives, one male and one female. They are at a crime scene--a bedroom--and the male says, "Now, when I switch on this special blue light, any traces of the suspects sperm will show up."

The detective switches on the light and there's nothing there. He looks up to his female colleague and guess what? Her face is glowing in the tell-tale signs of the facials she's recieved. She's like, "What? Why are you looking at me?"

Does anyone know what that was from?