I built this hybrid mobile app using PhoneGap/Cordova as a Studio Project when I was working for Social Design House. We wanted to be able to just play music based on the current weather - or some weather condition that you wanted to hear music for.
We leveraged 8tracks to get playlists and I ended up spending more time listening to music and decide what tags should map to what weather conditions than I did actually coding the app. For some reason I thought I jQuery plugin was the ideal way to interface with the 8tracks API and also released a small open source library for handling that: jquery.eightTracks.
After release, it was almost immediately ripped off by an enterprising developer in Veitnam who just repackaged our app with advertising added in. It took awhile to get his app removed from the App Store, and his seemed to just be approved without much question while we had to spend some time going back and forth with Apple about the background audio capability.