jQuery-Anchor Automatically highlight the #anchor clicked (or linked in the address bar)
jQuery-CollapsableTree collapsable tree, with cookie persist
jQuery-ModalFrame Open the selected link into a new iframe, shown on modal on the page
jQuery-PseudoClasses Add css3-pseudo-classes-like to the elements selected so the css3-unsupported browsers could still offer similar functionality in css2
jQuery-TreeAdorner automatically add handle (for collapsableTree in example) to a tree structure