Jquery

The concept of organising your JavaScript to this level may seem alien to some, but the advantages are limitless. This greatly improves maintainability and scalability, and as JS gets more and more advanced, so will the structure (from an architectural point of view).

Some of the best browsers to date have improved their JS rendering engine so much that you can basically build a full fledged application and wouldn't be able to tell the difference between a stand-alone app and the one running in your browser - amazing huh? Have you ever heard of OpenGL? Well, they're also coming out with WebGL, which will obviously be powered by JavaScript - say bye bye to flash and hello JS. If this alone doesn't convince you that it's growing extremely rapidly, then I don't know what will.

If you're maintaining a blog and want a way to highlight code within your articles (for ease of reading), then this article may interest you.

I can't even begin to say how annoying it is to read a large chunk of code that has no color highlighting - this will improve readability and traffic to your blog (or whatever you decide to use it on).