Microsoft and EA have launched a Facebook app called Mission Command, which rewards diligent fans with a variety of prizes and opportunities.
The app, available from the official Xbox page, challenges players to complete "missions" in return for prizes - the first reward on offer is a Normandy prop for your avatar should enough players download the Xbox 360 app.
Future missions are detailed on the rules page, and range from making an Omnitool and taking a photo in a public place, to creative writing, to solving puzzles. Prizes on offer include Mass Effect merchandise, vouchers, consoles and accessories.
The app doesn't appear related to the cross-platform Galaxy At War system, with which players can affect the events of the core game by playing multiplayer missions and using mysterious mobile and handheld titles.
Mass Effect 3 is due on PC, PlayStation 3 and Xbox 360 in March.