CSS / XHTML Compliant ASP Calendar description

A friend recently asked me to help him with a booking form he was creating for a website. The key thing he couldn't do was have a simple popup calendar (date picker) that a user could easily select a date from which would then fill out the date field on the form when clicked. Joy of joys I thought - at last a chance for me to do a little dabbling in the world of ASP.NET - I'd heard great things about the calendar control (3 lines of code and your done, etc). Alas I was to be very disappointed. It seems that Microsoft still have many lessons to learn when it comes to clean HTML and CSS implementations. The code produced by the ASP.NET calendar component was awful, difficult to customize and downright heavy. "Sod this" I thought, I'll script one up myself, now rather than reinventing the wheel, I discovered that Veerle (veerle.duoh.com) had already put a lot of effort in to producing a CSS styled XHTML calendar layout so I used the HTML of that as the goal for my script to produce.