Slingshot enthusiast designs and makes an effective slingshot. Probably could have thought the demonstration through a little better, though.
*WARNING* Contains a fair amount of blood at the end, and it doesn't appear to be faked /staged. Hope it's not a R, as someone just linked it to me, and I haven't seen it before anywhere.
http://www.liveleak.com/ll_embed?f=24113d89dfd8
Yeah, here's the how-to on his fake video:
"Untiteld" - The Making Of - YouTube