Developer area/code have put their location-based PC game Plundr onto the Nintendo DS -- the first of its kind, according to their website -- and showed it off at Where 2.0. The adventure game utilizes a Wi-Fi positioning system to give you different islands based on your physical location.
At each island, your pirate can buy, sell and fight for goods. According to the game's website, "depending on where you are in the physical world, you'll find different islands, different market prices and different ships to fight." You can try the PC version here, but desktop owners won't be able to enjoy it. The DS is one of the most portable options around, and we'd love to try this out. Pictures of the DS game can be found on Flickr (one, two, three).