Props to Colaab and SchoolMaster; two nice looking Silverlight applications with very compelling functionality. Collab has been designed for people to upload, review, and collaborate on content in real time. I can imagine some great experiences this application will provide such as enabling design reviews of application Ux for geographically dispersed teams and many others. School Master targets the educational market in the Netherlands, and allows users to manage parent details, student addresses, grades, etc... Both of these application are visually attractive too (can't beat that)!
Check them out!