Yehuda Katz, member of the Rails core team, describes the many new ways to extend Rails 3, including the overall philosophy of extending ActionController and how to use ActiveModel to better integrate your non-ActiveRecord Ruby objects and Rails.
Lew Cirne, CEO of New Relic, outlines how they use their own RPM product to maintain and improve the performance of their application, which processes billions of transactions per month with the average response time under 40ms.
Tammer Saleh of thoughtbot demonstrates Hoptoad, their Rails exception notification service. By aggregating repeat error notifications Hoptoad stops the email onslaught from a production bug while still providing appropriate notification and escalation.
Ezra Zygmuntowicz of Engine Yard demonstrates Solo, their new cloud offering for the deployment and management of lightweight Rails, Merb, or Rack apps.