So, everybody out there probably saw this XBox 360 tracker application from http://untitlednet.com/. I know that I've heard reports of links of this thing smoking through offices faster than a "it's Friday so you can leave an hour early" email.
Craig takes the idea and really kicks it up a notch, while at the same time showing off some cool features that will ship as part of WinFx. Go check out the code, and I'd like to point out the way that he uses workflow as a means by which to organize all of the work that he needs his application to do. He also shows some ways to get your workflow instance to communicate back to your user interface.
Check out this channel9 video that documents the approach he took, and how he leveraged these technologies, WCF, Workflow, and WPF in order to create a pretty sweet application. Now I just need to find an XBox 360 in Seattle!