I am not saying that the YUI is the best framework out there just because I work at Yahoo! and Dav would come over to my cube and throw a beat down.
YUI is the best for a number of reasons. My tinkering with YUI live here.
Creating a number custom events and subscribing to a number of the YUI Data Table events to trigger in page DOM manipulations
Technologies utilized on here include: the oh so sexy Yahoo! User Interface library and are used according to the terms of the Yahoo! BSD license. All other markup and styles for this page coded by me in TextMate. Though I work for Yahoo!, the opinions and ideas expressed here are mine and mine alone, and should be construed as any sort of corporate position from Yahoo!