Gah...I know this is two in a row, but I had to do this.
Instrumental group (Liquid Tension Experiment) featuring John Petrucci on guitar, Mike Portnoy on drums, Jordan Rudess on keyboard and Tony Levin (of the Peter Gabriel band and King Crimson, among others) on one of the coolest instruments on the planet: the Chapman Stick. Was listening to the studio version but found this live one that is so very well done.
http://www.youtube.com/watch?v=nqaM4ynvylc