Intro to Rails tutorial
Spend three hours getting your head around MVC, Ruby/Rails differences, what files are where, etc. to get newbies on board and ready to dive in to the sessions. This could be a walk through of the example apps in AWDWR (maybe the PragProg guys would want to host it?), or any kind of building a basic app. Lots of people come to RailsConf without having been a part of the culture for long, and providing a basic on-ramp to the deeper level topics would be a great service.