Look what I found today!

Prototype is a JavaScript framework that aims to ease development of dynamic web applications. Featuring a unique, easy-to-use toolkit for class-driven development and the nicest Ajax library around, Prototype is quickly becoming the codebase of choice for web application developers everywhere.

What I'm most interested in is how I'll be able to use it with Opera 9 Widgets. There are some pretty nice prizes available, after all. :)