Expanding Upon Learn WordPress
Learn WordPress at http://learn.wordpress.com is the guide for WordPress.com users as well as a great guide for new WordPress users. We’re working on expanding topics covered by Learn WordPress in the WordPress Lessons section of the Codex, taking the basics and digging in a little deeper to flesh it out, as is appropriate for our online manual for WordPress.
Take a look and see what they have been covering and pick a topic and let’s see what we can do with it.
Recent examples include: http://codex.wordpress.org/Comments_in_WordPress and http://codex.wordpress.org/How_to_Use_Gravatars_in_WordPress