Reminded me of the navigation on a javascript documentation website posted a little while ago : http://bonsaiden.github.com/JavaScript-Garden/

I am seeing more and more of these all over the place and I think they are great for long pages! Would love to see more of them instead of table of contents on documentation websites (for example, using something similar on a site like the HTML5 spec : http://www.w3.org/TR/html5/ would make the navigation a lot more efficient)

Agreed! Was more impressed with the nav, but that's probably because I'm on old hardware/slow connection so the slideshow was very sluggish for me.