Lot's of iterations of this floating around. I did a remix of that a few years ago. The original had a commercial soundtrack and I did a royalty-free version as well as long/medium/short versions for a colleague to use in his talks. The newer ones have nicer graphics. This is what the original (circa early 2007 with remixed music) looks like:
http://nostatic.com/work/knowFull.mov
http://nostatic.com/work/knowShort.mov
Always good for a bit of perspective...
And just for grins, a talk I gave in late 2006
http://nostatic.com/work/diyTimed-web.mov