There is a lot of experimentation in pervasive mobile gaming right now.

There's still a certain novelty and the long-term appeal of games that rely heavily on this is uncertain. Witness the mobile game Foursquare, which could just be viewed as a ploy to get people to gather valuable geodata for free.

If you're looking for something a little more edgy, have a look at Blowtooth:

Blowtooth has been developed to explore the limits of pervasive gaming in public spaces where the constant surveillance of law-abiding and innocuous behaviour has become the everyday norm.

The game is specifically designed to exploit the affordances of a particular class of public space - namely international airports - in which people are subject to particularly high levels of intrusive surveillance and security monitoring. Even in everyday experience (i.e. outside of a game) such surveillance can be both simultaneously thrilling and frightening; the possibility of harnessing these sensations in a game - or indeed any other art form - has great potential.

Blowtooth is further designed with a fictional narrative theme that is deliberately provocative given the environment in which it is set i.e. the game-play involves the covert smuggling of drugs through airport security checks. In reality, of course, no drugs are involved and the game simply polls a player's vicinity for Bluetooth devices, produces a list of these devices and allows the player to conceptually dump or retrieve contraband on or off one or more devices in the list. No interaction with the other devices - or their owners - is made other than to discover the anonymous and factory allocated hardware addresses.

Obviously, be extremely careful not to brag about your achievements in the game within earshot of airport staff.

According to some reports, people have already had travel problems for mentioning it on Twitter.

Blowtooth is available now for the iPhone with an imminent release for phones which run Android, e.g. Google's Nexus One.