jQuery Demos

jQuery 

   UI  stuff - jqueryui.com.  (DatePicker is cool, I like the UI Darkness Theme)

   Plugins - http://plugins.jquery.com/ (EasyNews is nice, Agile Carousal is sweet)

Special mention:

Matteo Bicocchi’s (mb.ideas.repository) : Must check this out

(I love the mbGallery and mbMenu)