It will probably not be a big surprise that jQuery Highlight plugin can be used to highlight pieces of text on a page.
#highlight
Prism
Prism is a new lightweight, extensible syntax highlighter, built with modern web standards in mind.
SyntaxHighlighter
Syntax highlighting class developed completely in JS. Pretty impressive.
sfPropelActAsStarredBehaviorPlugin
sfPropelActAsStarredBehaviorPlugin
star propel objects ala Gmail star