Aka, colliding MD5, but in a very cool 12-way demonstration:

We have used a Sony Playstation 3 to correctly predict the outcome of the 2008 US presidential elections. In order not to influence the voters we keep our prediction secret, but commit to it by publishing its cryptographic hash on this website. The document with the correct prediction and matching hash will be revealed after the elections.

Read all about it at http://www.win.tue.nl/hashclash/Nostradamus/

(yes I share my first name with one of the authors, but you’ll notice that the last name, while similar, is not identical – it’s really not me. I’m not that much of a maths or crypto whiz ;-)