sketchpad : compose
Want animation, but worry about the drawbacks of Adobe Flash®? IE lack of support on some operating systems, cost of the development environment? Then maybe processing.js is for you!

Processing the language is actually a Java library. Processing.js is the Javascript port, which will run natively in a browser, without any plugin.

Want to try it out? Sketchpad is for you. Just modify the code in the left window, press CTL-R, and the resulting animation runs to the right. Easy as custard pie.

Want to see what others have done? The site has many game examples, but here's one with a knowledge web--maybe the future replacement of Wikpedia, who knows? Ask Ken--I asked about Baron "von Steuben", then "quark".