Calendar
Download Calendar (rc4)
by Aeron Glemann | http://www.electricprism.com/aeron/calendar/
Calendar is a Javascript class that adds accessible and unobtrusive date-pickers to your form elements
Download DatePicker (1.16)
by Monkey Physics | http://www.monkeyphysics.com/mootools/script/2/datepicker
Smoothly animating and very configurable. No Ajax - pure Javascript.
Will work for any date-format and even supports time-picking. 4 skins ready for download.
Download Calendar EightySix (1.0)
by Base86 | http://dev.base86.com/scripts/datepicker_calendar_eightysix.html
Calendar Eightysix is an unobtrusive developer friendly calendar and datepicker, offering a better user experience for date related functionalities. The successor of the popular Vista-like Ajax Calendar.