Grid Calculator
Grid Layout (ctrl+shift+g)
The Grid Layout Javascript enables web-developers to stick to a Grid Layout quickly and simply by including the Grid Layouts Javascript file and simple XHTML code. Currently, the Grid Layouts Javascript relies on jQuery.
wg:Filler text on demand
See related links to what you are looking for.
Yahoo! UI Library
Big Player opens UI Library
CSS
script.aculo.us - web 2.0 javascript