Lighter.js is a free syntax highlighting class developed with MooTools. It was created with the MooTools developer in mind and takes advantage of many of the Framework’s features. Using it can be as simple as adding a single script to your webpage, selecting the elements you wish to highlight, and Lighter.js takes care of the rest. Lighter.js has been tested on Safari 2+, Internet Explorer 6+, Firefox 2+ and Opera 9+.

Requirements: MooTools Framework
Demo: http://pradador.com/code/lighterjs/
License: MIT License