Though a bit more on the "actual implementation" side of things, there's an Australian group called "Axis Of Awesome" who did an interesting song called "Four C

Though a bit more on the "actual implementation" side of things, there's an Australian group called "Axis Of Awesome" who did an interesting song called "Four Chords". It shows the use of a set of four common chords in a lot of different songs. http://www.youtube.com/watch?v=oOlDewpCfZQ http://www.youtube.com/watch?v=oOlDewpCfZQ