We've started a brand new series of series! We are turning the great O'Reilly book, Using Drupal, 2nd Edition, into videos lessons. Instead of being just one series, it will be thirteen individual series—one for each chapter of the book (plus appendices). We've created a new guide on Drupalize.Me to house the new series as they come out, and you can see that the first two are already up there. In addition to the first series, About the Using Drupal series, the first video from the Drupal Overview chapter, "What is Drupal?," is also free.