function set_up_calendar () {
	$('td.highlighted').Tooltip({
		track:true,
    		delay: 0,
    		opacity: 1,
		bodyHandler: function() { 
			var tooltipdata="";
// 			Construct the full date using the contents of the table cell (date) and
// 			the year and month, which are in a hidden header h5 at the start of 
// 			the calendar table.
// 			This date is then used as a class selector to pick out the data to be shown
// 			in the tooltip. Simply add the class yyyy-mm-dd to any div to make it part
// 			of the tooltip!
			var calmonth=$(this).parents('table.calendar:first').prev('h5.hidden').html();
			var dateclass='.'+calmonth+'-'+$(this).text(); 
			$(dateclass).each(function (){
				tooltipdata = tooltipdata + $(this).html();
			}); 
			return tooltipdata;
    		}
	});
	
}