If you are an Open XML fan (like me), I strongly recommend you check out the latest news shared by Doug Mahugh and Wouter van Vugt. Doug released all the ppt files, code samples, and hands-on labs content for the Open XML developer workshop. I attended this training and I can tell you that I owe much of my understanding of Open XML to Doug and his superb workshop.
Also, Wouter wrote the book "Open XML Explained." He did a pretty amazing job explaining WordprocessingML, SpreadhseetML, PresentationML, and DrawingML. The best thing is that you can get a free download.