From December 26th until January 6th, Apple will give away a selection of books, apps, songs, movies and TV episodes for free. The app doesn’t show much right, except that it asks you for push notification authorization and it displays a countdown to the daily giveaway on screen.
The app is not available in the US Store, I downloaded my copy from the UK one. I guess it should be available in other European stores as well. If you have a UK account, you can go download the app here