I'm curious if anybody here has heard of or plays Ingress? Ingress is a mobile online game currently for Android phones (I think there's an iPhone version coming soon) where it integrates the real world (via Google Maps) into an online game. You are an agent fighting for either the Resistance or Enlightened factions. Real world objects such as stone monuments or landmarks act as "portals" that your faction must claim and protect (sort of like a Capture the Flag/King of the Hill sort of game) and you can combat or team up with other agents to attack or protect your portals. It's an interesting concept that augments reality into a game.
What I like about it is, it encourages you to go out and explore the real world to claim your portals.
Here's the wikia on it: http://ingress.wikia.com/wiki/Main_Page