(YAWF – Yet Another Web Framework)
Cappuccino is a framework for writing desktop like applications on the web. The focus of the framework is to forget about page and links and create a model that acts like the desktop GUI model.
The guys that created Cappuccino did that in order to create 280slides , so check it out to see what Cappuccino is capable of.
An IDE for cappuccino is in the works and there's a video demonstrating it. The demonstration also shows how the GUI is created by linking the widgets (a concept from Cocoa), without writing any code.
A high level introduction presentation is available here.