function openCalendar() {
	var h = jQuery(window).height()-160;
	jQuery('body').prepend('<div id="overlayBackground" onclick="closeCalendar();"></div>'
		+'<div id="overlay" onclick="closeCalendar();">'
		+'<div class="inner" onclick="event.stopPropagation();">'
		+'<iframe src="https://www.google.com/calendar/embed?height='+h+'&amp;wkst=1&amp;bgcolor=%23FFFFFF&amp;src=eglp1gdqgl2i9gc01io53fer8k%40group.calendar.google.com&amp;color=%235C1158&amp;src=rpp8d4qesu0qdps4tfkn18v4g8%40group.calendar.google.com&amp;color=%23125A12&amp;src=0vr27p8q3j2jedsj78ngc7rpp8%40group.calendar.google.com&amp;color=%23333333&amp;src=66kt39f8o7hpi5569l9snrum48%40group.calendar.google.com&amp;color=%23AB8B00&amp;src=gublgdn5j7iunsnsr4k1vf02kk%40group.calendar.google.com&amp;color=%23711616&amp;ctz=Europe%2FPrague" style=" border-width:0 " width="800" height="'+h+'" frameborder="0" scrolling="no"></iframe>'
		//+'<iframe src="https://www.google.com/calendar/embed?showTitle=0&amp;showNav=1&amp;showDate=1&amp;showPrint=0&amp;showTabs=0&amp;showCalendars=0&amp;showTz=0&amp;height='+h+'&amp;wkst=2&amp;bgcolor=%23FFFFFF&amp;src=eglp1gdqgl2i9gc01io53fer8k%40group.calendar.google.com&amp;color=%235C1158&amp;ctz=Europe%2FPrague" style=" border-width:0; margin: 0 3px; margin-top: 15px; " width="800" height="'+h+'" frameborder="0" scrolling="no"></iframe>'		
		+'</div>'
		+'</div>');
	jQuery('#overlayBackground').css('opacity',0.8);
	jQuery('#overlay .inner').height(h+20);
}
function closeCalendar() {
	jQuery('#overlayBackground,#overlay').remove();
}