Silverlight in the TechEd Keynote
I just noticed that they posted the full keynote from Teched 07... I encourage you to watch the whole thing (especially the first few minutes on the Back to the future gag where Microsoft makes fun of ourselves a bit)..
The Silverlight demo is at 1:19... there Jamie Cool does a very compelling demo of Silverlight, shows off some applications and just a bit of code.
Enjoy!