Drupal Dojo provides (more or less) weekly on-line lessons on all topics revolving around Drupal. Many of these are fairly intensely developer oriented, but they're always interesting.
We've been seeing an increasing interest in CIviCRM from clients. The CiviCRM people have been creating a series of screencasts on using CiviCRM. This is the introductory video from the series.
This is a very useful write-up on how the School of Everything uses taxonomy and notifications to keep their members up-to-date on what is going on on the site.
For those of you of a more technical bent - when you build your Drupal site, do you ever wonder if you're making the right choice for database engines? I know I do - this article will help.
The scheduler module is one way to schedule the posting, unposting, etc. of content in Drupal. This screencast steps you through using the scheduler module.