Ingress is played on a mobile android device. It is an augmented reality MMRPG. You can download the app free from the google play store (that is a screen shot of the app, called the "scanner", in game-play in the first post). Since it is in beta you need an invitation to play, and since I have been playing since the game was released last Thanksgiving I have several invitations available if anyone is interested.
Basically it is a sci-fi game that uses the entire world as its map in real time, and you compete against other players in real space in real time. All players are divided into one of two sides, the Enlightened, or the Resistance. So there are basically 2 teams worldwide. It is highly cooperative as to really get anywhere in the game you need to work with other players.
The creators of the game have built an in-depth and detailed sci-fi story that deals with inter-dimensional beings trying to infiltrate the earth, with the 2 sides in the game either supporting the invasion (the Enlightened) or attempting to stop it (the Resistance). These being are attempting to enter our world through "portals", that emanate multi-dimensional energy used by the "scanner" app to play the game. These portals were initially set up using the Historical Marker Database.
https://www.hmdb.org/
In essence, every historical marker on the planet, at least those that are in the database, which is pretty extensive, is a "portal" and are locations to play the game. You claim a portal for your side, and the other side tries to reclaim the portal. Most public buildings (capitol, city hall, etc.), fire stations, and post offices are also portals. There are weapons and defensive devices to use in the battle. Recently they have been accepting submissions for new portals from the players, so there are new ones coming online all the time. In bigger cities (L.A., New York, Berlin, Tokyo, Moscow, Beijing, etc.) there can be thousands of them. Even here in the Reno area there are well over 100 of them, and over 40 in Virginia City, since every freaking building up there is labeled a historic monument of some kind. Salt Lake City has a lot too.
It works on a level system as well as a rewards system of sorts. You gain experience by playing the game, and get to higher levels which unlocks higher level stuff to play with, for weapons and defense. But there is another facet of the game in which you attempt to control as much of the game map for your side as possible, with large tracts changing hands among the 2 factions with regularity. This is where cooperating game-play come in the most, since you need to work with other players to really take control of large areas. You do this by linking portals together in a triangle to form fields that cover the space in between. It then records a score of the estimated population living in that triangle. Currently the score is around 28 mill apiece. It is fairly evenly balanced, but the Resistance outnumbers the Enlightened, in terms of players playing the game, by close to a 3 to 1 margin, much higher in some areas. In Reno it is more like 5 to 1.
There is a map of the playing field (i.e. the world), showing every portal and field created by linking portals, available for registered players at
https://www.ingress.com/intel
Here is an intel map image showing portals and a field:
It has been interesting as it is in beta so they are developing it as we are playing it, making changes and upgrades according to the community voice. I was involved in other beta testing in the past (most notably the original Doom, Doom II and Quake, since I have a mutual friend with John Carmack), but this has been something entirely different. You don't have to wait until the game is in full release to see a lot of the tweaking they have been doing to the code, as it happens in real time. It is also interesting playing real people. I have had many duels with people in real-time over portals and fields, and met many players on both sides of the game. It's really pretty cool.
https://en.wikipedia.org/wiki/Ingress_(game)