Perplex City

I somehow came across this idea today of ‘Alternative Reality Games’ along with an example of one at www.perplexcity.com - I’m still not entirely sure how it works, but it seems to be launching in June. The idea is that there is a hidden object somewhere in the world (a cube) which was stolen, and you have to find it. There are clues on leaflets, websites, posters etc. and you can also buy 6 cards with clues on for $5 or £2.50… the person who finds the cube wins £100,000 or $200,000 or €150,000. It seems really interesting, I wonder if any of you know more?