There are now a handful of code snippets from Wouter available over on the openxmldeveloper.org site that you should check out. He's been pulling these together over the past couple weeks, and they are really looking good.
Here's what he has up there so far:
- Building Open XML documents with code snippets
- WordProcessingML Snippets: Part 1, utility snippets
- WordProcessingML Snippets: Part 2, basic paragraphs
- WordProcessingML Snippets: Part 3, table structure
It sounds like his next step will be to get a bit more detailed on the WordprocessingML table details. The OpenXMLDeveloper folks are also asking anyone that has additional snippets they'd like to see to send the suggestions on in: http://openxmldeveloper.org/contact.aspx