This morning, @dslrinfo on twitter posted the link to this high-speed video of the Canon EOS 5D (not the mk2) shutter firing. Nothing earth shattering here, just fun to watch! Sure makes you appreciate the mirror lock up function doesn't it?
UPDATE: if you want to see the 50D and the Xt shutters (and a few other canon cameras) there are more videos on smugmug.
(Photo credit: snap from the video)