I have finished coding a Joomla 1.5 module called ArticleAccordion, which produces the articles needed in a particular area in the form of an animated Accordion.
The articles are enumerated top-bottom, latest-oldest, Year -> Month-> Articles. The first Month opens automatically. Clicking to another month auto collapses. jQuery is used to handle the accordion animation.
So if you use Joomla, or think you need to crack open some code to see how an Accordion works, download it and try it out.
GPLv2 applies. No warranty expressed nor implied.