Well, perhaps I'm exaggerating a little (!), but we've just posted a great 20-minute screencast from Fil Fortes (one of the PMs on the WPF team), who builds a XAML browser application from scratch using XAMLPad, Visual Studio 2005 and Expression Interactive Designer, based on the February 2006 CTP of the WinFX Runtime Components.
This is a really awesome demo, because it encapsulates a bunch of the key concepts of WPF: styles, templates, data binding, imaging, XAML, and tools workflow. There's not a wasted moment - just pure "meat". If you've any interest in UI technologies, you'd be mad to miss this.