One of the appealing aspects of YUI3 in the mix is that it acts a natural deodorant - follow the wafting aroma of YUI3 to help avoid code smells.
Satyams Delight - A detailed recipe from the tastemaster.
Reusable Widgets - Ryan Grove shows us a nice base setup
Eric Fs Full Service Diner - Full app powering http://photosnear.me/
Eric Fs Component Manager - Because a clean kitchen is a healthy kitchen, and a prepared cook can take advantage of being lazy.
YUI3 SchemApp - JSON-Schema powered YUI3 Apps
Mosens YUIBuild - Community build tool for YUI3 modules ( and other things ), lints, strips, minifies and concatenates so you don't have to - using Node.js as a bonus.