Google has just released their Google Web Toolkit, a development library/toolkit for web applications which supposedly powers Google lines of products. It is still in beta, but available for download. It runs on both Windows and Linux.
I guess I would like it more if I am still doing web development in Java. I understand that Google is a Java/C++/Python company, and from their point view it makes sense -- good debugging environment, familiar language, etc. But limiting GWT to JDK would surely limit its usefulness to the others in the web development community.
Update: James Tauber asked about Python's equivalent to GWT, and comments provide helpful links to other similar projects. Now that's less code!