Learning Javascript

Over the weekend I decided to do some reading about Javascript.  Specifically, I’m interested in some of the libraries available to make website a bit more fancy.  With the growth of web apps lately, there has been a lot of good work to add more abstractions to the javascript stuff.  Now it’s very easy to add something like a calendar dialog to a website.
The ones that I looked into are jQuery, which seems really nice, but it’s more of one level of abstraction above the DOM.  it just provides an easy way to insert HTML into a page, or do an AJAX request, and there’s some animations mixed in there.  It definately made the code more readable than straight up Javascript
The Yahoo User Interface (YUI) library provides some higher level things.  Calendars, sortable tables, animations, as well as the AJAX stuff.  It seems like a  pretty quick way to get a nice looking web app up and running.  I’ve downloaded the code and started playing around with it at home.  I’m hoping that I’ll be able to use it at work in the near future.
Dojo is one that I used a while ago, and I was both impressed with the high level of built in functionality, but also not some impressed with how easy it was to expand on, or change the look.  This one provides some really high level stuff, like checking text boxes for valid email addresses automatically.
I’m hoping to find a small project which I can try out some of these things.
At work we’re in the process of replaces our old database with a modern one.  As part of the transition we’ll be looking at moving some of our apps to web based versions.