Go Free Range worked with Mudlark from March to September 2010 to help build Chromaroma, a game you can play by travelling around London.

Using an Oyster card users swipe in and out of tube stations, ride the overground and jump on buses, accruing points for themselves and their team. The game includes missions, collections and achievements which can be unlocked via game mechanics such as location, time and speed.

The game is open to the public now.

Check it out: http://chromaroma.com