I'm a big fan of ExtJS and have followed YUI for a very long time (since before ExtJS leveraged it), the whole concept behind Mojito is akin to a completely pluggable architecture that makes use of the best parts of Node.js and integrates (using the MVC pattern) with YUI 3.
Check it out even just for a look se:
My latest app is an iPad application that captures project status information for activities, software releases or projects that that you are working on.
I had originally planned a much larger feature set for the first release but after reading two Agile/Scrum articles I decided to stick with the philosophy 'release early, release often'.
As much as I like WordPress (and I do) I ditched my previous installation and hand coded the Landing Soon website - www.landingsoonapp.com