Don't Put Your Hand in the Large Hadron Collider
In this video, a variety of scientists are asked this simple question: "If I put my hand in front of the beam at the Large Hadron Collider, what would happen?" Their answers are all over the map, but generally they agree that it's not a good idea.
A few sample answers: "Don't know."; "Not a good idea. Wouldn't recommend it."; "Gosh. Um. I don't think you'd feel very much."; "It'd probably be very bad for you and they'd be very cross with you."; "That synchrotron radiation is very nasty!"
For those of you who don't remember the LHC, read up on it, or just listen to the Large Hadron Rap by CERN employee Katherine McAlpine.
Note: after the first four minutes, this video gets into other topics that aren't quite as amusing, but still worth a look.