Via Tim Sneath:
"Celso Gomes is an amazing interactive designer working at Microsoft who is responsible for the beautiful sample applications that ship with Expression Blend and did some of the earliest design explorations for Silverlight.
Now he's come up with Nibbles: a series of "snack tutorials for hungry designers" that cover the use of Expression Blend to build WPF and Silverlight content. The site itself is a stunning example of Silverlight, with faded animations and transitions and accordion bars: it makes my own work seem feeble by comparison. Make sure you check it out - it's inspiring..." 
It is pretty cool. This is the first Silverlight based site I've seen that actually looks like a Flash site. Almost everything else I've seen has been a sample made by a developer, not a designer, if you catch my drift ;).