Framework for developing RIA Web 2.0 applications. LGPL

Humax 0.2 provides a rich set of object-oriented client-side libraries which work seamlessly regardless of the server side technology used.

Ajax Java Web framework that enables rich UIs for Web applications with little programming. GPL
ZK 3.0.1 With event-driven components and an XUL-based markup language, developing is as simple as programming desktops and authoring HTML. Scripting languages include but are not limited to Java, JavaScript, Ruby, and Groovy.