[VIDEO] Ingress was created by a startup within Google called Niantic Labs. From the Wikipedia page:
The gameplay consists of establishing “portals” at places of public art, landmarks, cenotaphs, etc., and linking them to create virtual triangular fields over geographic areas. Progress in the game is measured by the number of Mind Units, i.e. people, nominally controlled by each faction (as illustrated on the Intel Map).
Here’s a link to the iOS version of the game. It’s free. Note that you’ll need to login with a gmail or other Google account.
Note also that you’ll need to share your location with the game and that your location will be shared with other players. There is a bit of risk there, both in privacy and in sharing your actual location with people you don’t know. This is the one aspect of the game I find worrisome.
The trailer is embedded below.