I've written before about mashups, but I just stumbled across one I had to blog about.
Jonathan Coulton just put out a song about a programmer this week, which I loved and which prompted me to go listen to a bunch of his other music. That's how I happened across When I'm 25 or 64, which is a mashup of Paul McCartney's When I'm 64 and Chicago's 25 or 6 to 4, which are both songs I like. The end result had me sitting here listening with my mouth open. Take a listen.
Mission Impossible/Norwegian Wood (Alan Copeland)
http://www.daveamason.com/april/mp3/MissionImp%5FNorwegianWood%2Emp3