These guys are amazing and one of my all time favorites. They're like a really hard type of progressive/experimental kind of band; I really don't know how to describe them. Their singer is Anthony Green from the band Circa Survive, if you've heard of them. These guys have changed the way I listen to music.
Act IV: You Don't Need a Witness -
http://www.youtube.com/watch?v=UY1hm5UQDaU...feature=relatedAct III: Modulate Back to the Tonic -
http://www.youtube.com/watch?v=JwkNGVMXPTY - They're just jamming for the first minute of this one.