The talk covered a successful utilization of Rails Engines in a Rails 3 project to modularize MVC features as reusable components. These components provide the best of both worlds, improved productivity through reusable MVC code, and better flexibility by allowing different applications to customize behavior as needed without dirty conditionals by relying on the Extension Point pattern (as used in the Eclipse IDE). Of course, given the benefits of Ruby, no XML is involved in the extension points, but how that was accomplished is beyond the scope of the lightning talk and can be covered in a future blog post.
Check out the slides over here:
Follow-up one-hour long presentation has been posted over here: The Rails Engine That Could - In Motion