This app plays melodies with dog barking sounds. You can choose from 12 popular melodies such as Mary had a Little Lamb, Auld Lang Syne and others, shake the phone and watch the puppies barking it, then try to repeat by tapping on the dogs. All the melodies used in the game are in Pentatonic scale which is pretty cool. Entertaining particularly for little kids.
On side note, our little dog has actually seemed very interested in listening the songs but I am not sure if it would encourage him to bark even more.
Video demo is below and you can find the app and more reviews here.