Casey alerted me to the existence of Isle of Tune - a musical website that uses street layouts for loops, suburban placeholders for sounds and cars as instrument progress. It is incredibly difficult to describe but rather engaging to browse through. Start with something familiar like Pink Floyd's "Money", Michael Jackson's "Beat It" or even MGMT's "Kids" to get an idea of exactly what's going on.. and then try making your own. Even if you have no idea what you're doing (like myself), it's fun to tinker around with.