Ingress is an augmented reality massively multiplayer online role playing GPS-dependent game created by Niantic Labs, a startup within Google, originally for Android devices, and since July 14, 2014 for Apple's iOS. The game has a complex science fiction back story with a continuous open narrative.
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" (MUs), i.e. people, nominally controlled by each faction (as illustrated on the Intel Map).
The primary goal of the game is defend the takeover of the human race by an unknown “Shaper” force or, depending on your perspective, to assist in an “Enlightenment” of mankind through an alliance with the Shapers. This is accomplished by aligning with either the Resistance or the Enlightened faction and by creating “Control Fields” over geographic areas. Progress in the game is measured by the number of Mind Units controlled by each Faction (visible on the Intel Map).
A group of us spent an hour walking around Derby last week trying this. We never really understood what we were doing, so we went and got drunk instead.