The app is from Mibblio, Using "Mibblets," it's an interactive children's music story book that allow kids to read and jam along with the songs. Santa's Merry Band features music from KT Tunstall, Guster, Indigo Girls, The Brian Setzer Orchestra, G.Love, and more.
Emmy the Great & Tim Wheeler's awesome cover of "Marshmallow World' is in the app. mARTshmallows which is The Art of Designing with Marshmallows is giving away a copy of the book and a download of the app plus another 10 free app downloads. Get all the details here on their facebook page.
Enter on Instagram with your holiday treat ideas and use the hashtag #mibbliomarshmallows