It's a smartphone based game, sort of Geo-caching meets live action role play: https://www.ingress.com/
You basically have these virtual 'portals' which can be public art, interesting signposts, graffiti, plaques etc. and you have to build them by placing resonators, it takes 8 level 8 players to make a level 8 portal, so it's something of a collaboration game. If the portal belongs to the other team, then you should attack it with weapons. Three portals linked together created a mind unit control field.
I've been playing for just over a year now. My next door neighbors recently started playing, unfortunately on the 'other' team, so it's kind of annoying to keep flipping portals in the neighborhood with them. In-fact, the geezer thinks he got the last attacks in at 11pm by walking around, but doesn't seem to realize that I'm a night owl that doesn't typically drink, so I'm thinking about heading out to undo his efforts.
It's a lot of fun, it's now on Apple as well as the base Android. The company that develop it, Niantic labs, are owned by Google.
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