I haven't tried it out myself yet, but this stuff just looks amazing. It seems to perform pretty well, too. Ext JS is a JavaScript library that can easily create some desktop-like window effects. A coworker was demoing it with a table of data and the JavaScript automatically sorted, he could CTRL-select items and you can even drag things around. It seems to be an great open-source application. To get started, check out the documentation which includes some simple examples and the code to generate them. There's also some great examples such as DowJonesIndexes.com and an entire web desktop. Also, there's a sample desktop app that runs on your desktop via Adobe AIR or Google Gears and a full-function Feed Reader. I was trying to find some sort of cool widget to embed in this post, but I couldn't find something quickly. Tell me what you find, if you're interested.