Here are a few requests I've gotten for lessons. If you are an "expert" in any of these, please post them (with the title Lesson: and specific title) in the appropriate forum section. If you don't know how to say thank you for WordPress being free and open source, this is one way.
And thank you in advance!
* Working with individual "Pages" - all topics
* Understanding wp_list_cats()
* Understanding specific Template Tags
* CSS - the 3-column layout
* CSS bugs and hacks for browsers
* CSS - Moving the Sidebar Menu from Right to Left
* WordPress International Issues
* CSS - Styling Blockquotes
* Creating a Site Map or Table of Contents
* Developing Plugins of your very own
* Tracking down CSS errors
* Tracking down PHP code errors
* CSS - Making Your Header Stand Out
* CSS - Styling the Sidebar Menu with it's many lists
* Working with Nested Lists - Understanding the WordPress sidebar
If you have a topic you would like to see in a Lesson, please add it here. And if we have anyone duplicating each other's efforts, who cares. We have a lot to learn from everyone and the same thing may be done differently by someone else. No hard and fast rules here, but helping everyone out.