When developing enterprise applications, one is bound to have a need for a calendar to help the user fill in dates. I had a similar need so I went Calendar component shopping after a couple of tries I landed up @ http://dynarch.com/mishoo/calendar/cal.html. A really nice looking calendar popup. Its very rare to find a component that fits your need and look good, documentation is another story! But this component rocks! Its highly customisable and I have really good documentation. It provides example pages and quick notes on setup for folks with less patience like me 😉
All in all a great component, ever have a calendaring need make sure you give this a shot!