Office Interactive Developer Map: A Very Cool WPF Application
You've got to check out the Microsoft Office Interactive Developer Map and it's write up on the Sharepoint Products and Technologies Team Blog.
This Windows Presentation Foundation (WPF) application allows you to drill down to each product and technology and learn about new features, objects, Web services, namespaces, and schemas required to extend Microsoft Office and build custom Office Business Applications (OBAs).
If you've ever thought a building an application that involves Office integration you need this tool!