'Uncle Roy All Around You' was an elaborate experimental game across the streets of London. The scenario: You're abandoned on Tower Bridge, London, with nothing except your clothes and a mobile phone when a woman dressed in black walks past, and you receive a text message to follow her. You don't know who she is, or where she is going. All you know is that you must follow her if you are to find Uncle Roy.
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.
And in Uncle Roy, for example, not only does the game involve innocent bystanders - the woman dressed in black had no knowledge she was taking part in the exercise - but it culminates in the street player climbing into a stranger's car, which means the player has to trust the organisers.
These real-world games sound interesting, but they also sound dangerous. How far will a gamer go when ordered to do something? And eventually, how will they know if it's just a game, or if it's real life?