I've never used Prototype or YUI-JS extensively, but I've recently started teaching myself JQuery by simply making things. It's amazing how simple this framework is to use, so try it out.
Also, I find Prototype to be way to bloated, at least in comparison to JQuery. :)

» Your (javascript) framework of choice ... Last Reply: 8 months ago by JoeLencioni.
@Oli: Really? Wow, I just did a search on Javascript, as I was looking for some tutorials or such on JQuery. :)