After quite a few email conversations about HTML_Template_Flexy, I finally got round to documenting one of the javascript libraries I've modified. This is still a bit buggy around the edges, but is pretty much working.
Javascript Calendar started off with a few hacks around the dynCalendar on pear.php.net, and evolved into nice clean simple Calender renderer.
The main design criteria for this was that it should be independant of the HTML page, not requiring any specific javascript, or changing the backend Template code. Just include the javascript file, set the style, and add a few extra attributes to the input elements.