Angry Birds Rio, the Angry Birds tie-in game to the movie that was kind-of-but-not-really about flinging poultry, is free for a limited time. Rovio has made the game Apple's free App of the Week on iOS devices, just in case you haven't gotten enough Angry Birds from the various other releases.
The game is available on the App Store, and promises more than 200 stages of levels inspired by the movie Rio. The birds escape kidnappers from Rio de Janeiro, and then set about saving Blu and Jewel, the two characters from the movie. It's only free through January 24, so if you want to grab even more Angry Birds you should snag it while you can.