Rails is huge. Even if you have worked with it for a long time, it's unlikely that you have stumbled across everything yet.
Do you really know what all of the built-in Rake tasks do? Have you seen all of the methods ActiveSupport makes available to you? Are you aware of all the queries ActiveRecord is capable of?
In this talk, I'll dig into the extras of Rails and see if I can't turn up some features that you don't see all of the time, but that might just be handy to know about anyway. I'll make sure you come out of this able to impress your friends at the hackfest.