Toccata and Fugue in D minor, J. S. Bach
Bach's organ piece, with a scrolling score. Production notes for this piece are here:
This type of display can be generated from any MIDI file with this tool:
Note: If you have trouble with sync or audio quality, download the original (m4v) version.
There's a description of this piece in the viewer guide for the video (DVD) that contains it: