I recently did a talk at the Colorado iOS dev camp, spring 2013, demonstrating how to create music and video for your app promotion. I mentioned the idea of what I refer to as the Happy Appy song--a song that is really simple and has only a few defining characteristics:
1. A happy chord progression in a major key
2. A simple drumbeat
3. A glockenspiel sound
Watch the video and you'll understand what a Happy Appy Song is.