My 2011 GoRuCo talk, Less - The Path to Better Design, is at Vimeo.
It's mostly about reducing object coupling and is full of example code. If you occasionally find yourself forced into a corner where you have to write case statements that switch on class, have a look, this will help.
Plus, the last two and a half minutes are full of bicycles; what's not to like?
The slides are on Heroku.
Thanks again to all the GoRuCo organizers. The conference is great and is an accurate reflection of their commitment to the community.