Parallel Kingdom is a mobile location-based game from PerBlue that uses WiFi technology to create an MMO space on top of the real world. Upon downloading Parallel Kingdom to your iPhone or Android phone, you enter an MMO-world based upon your current location. While one can hunt and level up via some of the more typical RPG methods, finding others nearby who have downloaded the game is where the real potential lies.
Parallel Kingdom lets you chat with others, move from your start location, including via warp from others you know. the graphics are very basic, utilizing game graphics overlaid upon a Google map. Moving and restarting the game in a different area will open up a different part of the world to you. Players can claim land, build houses, and mark territory with flags that they can return to automatically if kept in sight.
Parallel Kingdom is currently free to download and play, and the developers are adding new features regularly. The game is now playable internationally, which makes possibilities pretty endless.