This time we have 2 variants in Origin's On The House giveaway. Medal of Honor: Pacific Assault and Dead In Bermuda are the two free games available. Your location will determine which game you get. Apparently, people from EU are getting Medal of Honor: Pacific Assault and others are getting Dead In Bermuda. So go to Origin and find out which game is available for you.
You'll need to login to your EA account to add the game to your Origin library. Once added, it'll be yours to keep forever. But you'll require the Origin client in order to play the game.
If you don't have the client, grab it here.