While running through Freshmeat, I noticed this UI library with a strange name: qooxdoo. I've seen quite a few of these before, and they all tend to be little more than a couple of draggable shapes. However, for things like HTA's and PHUI (which I'm currently using to build a Site CD Builder of sorts for CD-R copies of web sites, I want a more Windows-like set of widgets. In that kind of environment, making it look just like a regular app completes the illusion. At any rate, I think this one may actually be worth digging a bit deeper.
http://qooxdoo.sourceforge.net/
qooxdoo, web development, javascript, ui