Render view asynchronously.

partial_async.rb

First put an empty, placeholder div in the main response

<div id="pink-dancing-elephants"></div>
and then add a little jQuery to the page

$.ajax({
    url: "/elephants/dancing",
    cache: false,
    success: function(html){
      $("#pink-dancing-elephants").append(html);
    }
});
and have the action that responses to /elephants/dancing/pink return the blob of HTML that you want to have fill up the div. In the action that is invoked by the AJAX request, you'll want to render with :layout => false to keep the returned blob of HTML from including the entire frame. E.g.

# elephants_controller.rb
def dancing
  @elephants = #whatever
  render :layout => false
end