Alternate Reality Gaming as Promotion

I saw this story on Slashdot about some "alternate reality" game called "Perplex City". It's one of those games that bleeds over into real life, with physical clues to find in the real world, sort of like a big treasure hunt.

I haven't read the whole story on this particular game, but I've seen these in the past and I know some of them have been marketing stunts. But I think normally the marketing stunts are tie-ins for video games and movies and the like.

I wonder if such an "alternate reality" game would work as a marketing tool for a real life destination. I would think that liesure busineses in a downtown area could be banded together to create a cross-venue game. Perhaps the bartender in a nightclub would have the next clue, but only if you knew the secret passphrase which you'd have to learn by having attended a certain theatrical performance or perhaps seen a movie at the theatre next door.

It seems like a reasonable part of an economic development strategy for anyone trying to revitalize an urban area on its way up. I'd be interested to hear if anyone knows of anything like this being attempted.