some lil excerpts from the article to give you an idea what it's all about..
"...Matt is playing Uncle Roy All Around You, where for one day he is the main character in an elaborate experimental fantasy game played out across the streets of London. He also happens to be a pioneer of a new social phenomenon, urban gaming.
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For urban gamers are harnessing the power of global positioning systems (GPS), high-resolution screens and cameras and the latest mobile phones to play games across our towns and cities, where they become spies, vampire slayers, celebrities and even Pac-Man.
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Another phone-based game is a variant of the classic arcade game Tron. Two or more players, who may never have met, speed through a city leaving a virtual trail behind them that is plotted on their mobile phone screens. There is one rule: you can't cross your own trail or that of the other player, so the basic tactic is to try and encompass or corral your opponent, forcing him or her to cross a trail and lose the game. Pac-Manhattan players use PDAs incorporating GPS to work out each other's whereabouts..."
www.newscientist.com/channel/info-tech/mg18625036.200