Ever Suck in a Helium Balloon?

Of course you have, who hasn't?! But the real question is: Do you know why you sound like one the Chipmunks after taking a swing of the gas? Mythbusters has the answer - and not only does the debunker break down the explanation, but he also demonstrates the opposite affect sulfur hexafluoride. Check it out - assuming you promise not to try this at home, of course.