Yesterday, I gave a company presentation on jQuery and Rails. The talk covered details on how jQuery and Rails work together to build rich web applications, with a considerable amount of focus on AJAX methods. Check out the slides here:
One piece of knowledge I took away from the talk is how different the Rails 3 approach is for unobtrusive AJAX behavior using helpers like link_to_remote and remote_form_for. Mike Farmer made a recommendation to read the rails.js source here to see how onclick behavior is handled in Rails 3.