An amazing overview of Ajax Frameworks can be found here: http://www.maxkiesler.com/index.php/weblog/comments/round_up_of_50_ajax_toolkits_and_frameworks/ One framework that sticks out is Echo2 for Java (http://www.nextapp.com/platform/echo2/echo/). I still can''t believe what it can do even though I played with demos for two hours straight. I wonder if there is anyone out there crazy enough to try and port it to RoR...