The best resource for understanding how Drupal works is actually the handbooks at Drupal.org.
Learn By The Drop has some very interesting videos about setting up Drupal and some other basic info to get your site up and working quickly. I browsed their screencast about setting up FCKEditor and was very impressed.
There are also some very interesting screencasts at DrupalTherapy.com. In fact, I used the Date + Calendar screencast to setup my own event content type.
Lastly, a blog aggregator called PlanetDrupal is also fun to keep up with.
What are some of your favorite Drupal resources?