This is pretty cool: The Shape of Song.
The diagrams in The Shape of Song display musical form as a sequence of translucent arches. Each arch connects two repeated, identical passages of a composition. By using repeated passages as signposts, the diagram illustrates the deep structure of the composition.
You can select a song from the list and view its shape — or upload your own MIDI file. The shape below is, of course, one of the tracks from Pachelbel’s Canon.
From J-Walk Blog.