Last Friday we had the Pachelbel Rant where a cellist complained about the 4 notes he plays during the Pachelbel's Canon. He also talked about how there are so many songs that reflect the sound of Pachelbel and his one hit wonder.
Here is a fun study of the the 4 chord rock/pop music. When I taught a rock unit to young people I would have them at the piano playing the 4 chords as we sang along with various songs much like this fun Axis of Awesome does. Smart guys who can really sing.