Stealing this from W+K blog, this is by far the best facebook app so far.
Install, delete 10 'friends', yeah you know the ones, the ones you briefly met in 98 and have never spoken to since, then receive a free whopper.
It's amazing, the best use of a january spring clean for ages. I couldn't care less that the application notifies the other person that you have be sacrificed for a burger, must of the people I wouldn't talk to anyway!
Unfortunately it only works in the USA...for now.
Get your american burger a http://www.whoppersacrifice.com
I'd have given half my left arm for that idea to be in my book.