We have another Xen Document Day coming next Monday, which is March 25th.
Xen Document Days are for people who care about Xen Documentation and want to improve it. Everybody who can and wants contribute is welcome to join!
For a list of items that need work, check out the community maintained TODO and wishlist. We also have a few beginners items in the list. Of course, you can work on anything you like: the list just provides suggestions.
See you on IRC : #xendocs @ freenode !