The new Whopper Sacrifice promotion in the US works on a brilliantly simple idea, install the facebook app and delete 10 of your friends to be rewarded with a Whopper. So far over 200k friends have been deleted.
I love it, just love it. It's an online idea that offers something free, but is so silly and easy to pass on that you could imagine it going round millions of people. It's a promotion that makes you think, and that reinforces a positive product view.
If this is CPB, then welcome back to form.