Good Drupal Training

I have been using Drupal to manage several websites for a couple years now but really have not spent as much time as I should have in learning more about CSS and Drupal theming.  I have been relying on Drupal themes that others have put together and just making some very minor changes to the themes for the sites that I am maintaining.  I spent some time over Christmas break working on a new theme for my Blog site and for my 3 Day Team site.  To learn more about theming in Drupal I ordered some downloadable video tutorials from a group call the Lullabots that do training on how to do things in Drupal.  I have not made it all the way through both videos yet but they are already helping me understand the theming much better than I had before and I consider them a good investment.  The only problem I have now is having enough time to make all of the changes that I want to.