The idea of making music together with the people close to you inspired the Holiday Harmony app. Which means this app is best experienced with several of your friends all in the same room. Each of you can select the instrument you want your device to play and collectively you will make sweet holiday music together. Choose from traditional instruments and somewhat less traditional and of course you can add more cow bell.
Be sure to turn your volume up and the app will automatically sync with your friends near you so you can all play together.