“Script.aculo.us is an amazing framework for enriching your website’s user experience very easily. Built on top of the very popular prototype javascript framework, scriptaculous makes AJAX cake, and gives everyone the power to have a sexy AJAX-powered website, yes everyone. Scriptaculous is a tiny (140kb) javascript framework that gives you the power of effects, several dynamic data components, and all you need to know is a little bit about HTML and how to read. If you already have your own website, it is not hard to do. Follow these steps to AJAX up your site in no time.”
This libarary is great and has some really nice effects but it can be aquard to use… from time to time.. see the origninal Download Squad artical for the gorey details and a handy cheatsheet or visit the Script.aculo.us home page.