Once again, another snippet with emphasis on CSS rather than Javascript. The calendar on this page is actually a <select type="multiple"> element with <option>'s floated to the left!
The advantages of this are that you get a completely form-based solution to picking dates (or a range of days!). The example may be powered by Javascript, but it would be trivial to put some PHP behind the calendar and completely remove the browser-scripting requirement.
1.4 tree Gecko-only though, as Gecko is the only browser which doesn't put many limitations on styling form elements, and the 1.4 tree seems to have fixed a lot of rendering issues.
http://www.jasonkarldavis.com/calendar.xhtml
These experimental CSS things I've been doing may be useless in a practical sense, however when browsers catch up, they should be able to provide inspiration for the next-generation of effects.
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