When I start to learn a new language or framework, creating a small application really helps accelerate the learning process. Using the work I did for a MacTech article on test-driven development, I created a simple number guessing game as a Javascript web application (game page is here). I also used the YUI 2 YUITest testing framework to check out my Javascript functions as I developed them (test page is here). My next steps with this will be to try creating some browser extensions using this game as a starting point.