is-calendar is a very simple date picker for MooTools.
http://isfeng.github.io/is-calendar/
Snippet code HTML:
#HTML
<input type="text" id="cal">
Snippet code Javascript:
#Javascript
$('cal').makeCalendar();
// call back function
$('cal2').makeCalendar({
onSelectDate: function(d){
alert(d);
}
});
// change default color
$('cal3').makeCalendar({
bg_color: 'black',
date_color: 'white',
week_color: 'orange',
caption_color: 'white'
});