Payphone Tag is a new game (sport?) being played in Australia that uses the country's kinda-defunct public phone network and turns it into a geospatial game where you can claim whole regions of territory as your own, provided you're willing, Pokémon Go-style, to get out there and take it.
Australia's payphone network, built nationally throughout the 20th century at huge expense but rendered almost useless by the invention of the mobile phone in the 21st, underwent a huge transformation a few years back. Instead of ripping the things out, the people in charge had two rare, good ideas: not only did the network's operator (Telstra) make using the phones free, but they also turned every single booth into a free wi-fi hotspot.
Via Hackaday, Payphone Tag takes advantage of this by encouraging players to consult a map of Australia, find a payphone, get to it then make a free call, all the while pretending they’re in The Matrix. That phone call will prompt you to enter your own special PIN, and once you do that the booth is yours, and will be reflected on the game map. The more phones you visit, the more you can capture or steal, and stealing adjacent booths to form triangles will score you bonus points.
If you're in Australia and want to play, or aren't and just want to take a look at the maps and how it works, here's the game's site.
(Thanks Keegan!)
