Yesterday I attended an informative MSDN event in Ontario, California on CardSpace, AJAX Client Library and AJAX best practices. Lynn Langit did an excellent job explaining the concepts and basic implementation details. Even though it wasn't intended towards intermediate/advance developers, it's a good refresher if you are not actively using these technologies or want to get familiar with the topics more before you start. Hey, where else can you hear all the buzz words like Hijax!
Further details and goodies can be downloaded from Lynn's blog
Check for more MSDN Events in your area.