As far as in-game solutions go, you can either mod your Arenas/__init__.py or have a custom component that plays a song. As Craaig said, the easiest way of doing it is to mute the in-game stuff that you don't want to hear and start an external music player. If you have music installed on your computer, you can start XBOX Music or some other music application on windows 8 by htting Windows+S and typing in "Music" or whatever program you want to start. If you don't have any music, you can open up an online service like GTM Radio, Pandora, Jango, Spotify, or Grooveshark.
