As a general rule, I find that 90% of augmented reality is unnecessarily difficult (e.g. you point it at a print out and you see a character etc) and offers little in the way of true value to the user. So I was extremely please to stumble across The Hidden Park this morning.
The Hidden Park utilises GPS to overlay a magical park map over your location. Users are then taken on a journey through the game and can utilise the iPhones camera function to take aug. reality photos. The game is aimed to get kids out of the house, outside and interacting.
I have not yet had the chance to have a full play with this game, but from an advertiser perspective it shows what is capable utilising both GPS and Augmented reality technology. If an advertiser were a good fit this technology could be used to provide an amazing level of value to consumers, especially if we can extend the execution across platforms.