Metro-Wardive, a game for the Nintendo DS, uses the built-in Wi-Fi to detect hotspot activity around you and generates a unique gaming environment. Quoting from the website:

wardive captures the wlans in the immediate area like a wardive-tool and creates a game. it reads the names of the hotspots in your immediate area and turns them into enemies which try to take over your wardive-cristal. try to fend them off with your touch pen, put your shields up. and don't just stay in one spot. take metro-wardive for a walk or on a ride through town. find out how may enemies hide in the area you are in or pass through. each time you play,metro wardive captures different data and creates a new level for you. metro wardive is an adaptive game with locative levels. it changes according to its real life location as much as to its virtual data world.