I was looking for a screensaver, which is able to display some data (news, status etc) on my screen (linux and windows). I found an amazing, free and opensource Java-SDK with many samples. The SDK comes already with javadoc. The whole "framework" is very lean (5 classes), well designed and documented. It is also possible to start a screensaver in a JFrame for test purposes.
Combining SaverBeans together with JINI could be the first step into grid-computing or at least to JSeti :-)
NEW: Online Workhop Effective WebApps without Frameworks is also coming to: MUC Airport.