The Nintendo DS homebrew title Metro-Wardive converts nearby wlan waves into game objects. The software reads the names of the hotspots and turns them into enemies which will try to take over your "wardive-cristal." You'll have to fend them off with your stylus.
What is pretty nifty about Metro-Wardive is that it captures different data each time you play and generates a new level, keeping things fresh. It is "an adaptive game with locative levels; it changes according to its real life location as much as to its virtual data world."
To play, you'll have to download the game from their Web site. You'll also need something like an R4 or a Supercard to boot it.
[Via Game|Life -- Thanks, JR]