Harold laid down a wicked solo about Outside-In development. If you're fresh to the concept and haven't drank the BDD kool-aid yet, sit down and prepare to absorb some of Professor Giménez's testing wisdom. (diagram courtesy of this tutorial by Philippe Creux.)
The other headliner was my introductory tutorial to RubyGems, exposing some of their mystical secrets to new Ruby souls. Turns out they're not so mysterious after all.
Like these kind of tutorials? Let us know, we'd love to write some more.