Echo2 Web Framework: Web Apps with AJAX

freshmeat.net: Project details for Echo2 Web Framework
Echo2 is a reinvention of the Echo Web Framework built around an AJAX (Asynchronous JavaScript and XML) rendering engine. It aims to provide a component-oriented/event-driven toolkit for developing Web applications that approach the capabilities of rich clients.

I’m starting to see a lot of AJAX stuff and it is impressive.