YMMV I am not responsible for anything bad happening with this plugin. No support is given either, at least not yet. Use at your own risk!

This is a quick how-to on usage of the helper. The following is in my Event model

	function getEvents($params = array()) {
		$events = $this->find('all', array(
				'conditions' => array(
					"YEAR({$this->alias}.date)" => $params['year'],
					"MONTHNAME({$this->alias}.date)" => $params['month']),
				'fields' => array('id', 'slug', 'title', 'DAY(date) AS day', 'url'),
				'order' => "{$this->alias}.date ASC"));
		/**
		* loop through the returned data and build an array of 'events' that is passes to the view
		* array key is the day of month
		*/
		$data = array();
		foreach($events as $key => &$event) {
			$event[$this->alias]['day'] = $event['0']['day'];
			unset($event['0']);
			if (!isset($data[$event[$this->alias]['day']])) {
				$data[$event[$this->alias]['day']] = array();
			}
			$data[$event[$this->alias]['day']][] = $event;
		}
		return $data;
	}

	function getDateParameters($year = null, $month = null, $day = null) {
		if(is_null($year) or is_null($month) or is_null($day)) {
			$year = date('Y');
			$month = date('F');
			$day = date('d');
		} else {
			$monthList = $this->monthList;
			for($i = 0; $i < 12; $i++) { // check the month is valid if set
				if ((ucfirst(strtolower($month)) == $monthList[$i]) and (intval($year) != 0)) {
					$flag = 1;
					$month = $monthList[$i];
					break;
				}
			}
		}
		return array('year' => $year, 'month' => $month, 'day' => $day);
	}

My Controller:

	function calendar($year = null, $month = null) {
		if (!empty($this->data)) {
			$dataMonth = (isset($this->data['Event']['month'])) ? intval($this->data['Event']['month']['month']) - 1 : date('F');
			$dataMonth = $this->Event->monthList[$dataMonth];
			$dataYear = (isset($this->data['Event']['year'])) ? $this->data['Event']['year']['year'] : date('Y');
			$this->redirect(array('controller' => 'events', 'action' => 'calendar', "{$dataYear}/{$dataMonth}"));
		}
		$baseUrl = Router::url(array('controller' => 'events', 'action' => 'calendar'), true);
		$dateParameters = $this->Event->getDateParameters($year, $month);
		$year = $dateParameters['year'];
		$month = $dateParameters['month'];
		$events = $this->Event->find('calendar', array('year' => $year, 'month' => $month));
		$this->set(compact('year', 'month', 'baseUrl', 'events'));
	}

My view:

	<div class="events-calendar index">
		<h2 class="title">Calendar of Events</h2>
		<?php echo $calendar->calendar($year, $month, $events, $baseUrl); ?>
	</div>
	
	// Put the following in your head!
	echo $calendar->jquery();

Some very simple css:

/* Calendar */
#calendar_wrap{padding:10px 15px;text-align:center;}
	#calendar_wrap table{width:100%;}
		#calendar_wrap th{}
		#calendar_wrap td{}
			#calendar_wrap .day_header{display:none;}
			#calendar_wrap td.date_has_event .day{background-color:#555;color:#fff;-moz-border-radius:3px;-khtml-border-radius:3px;-webkit-border-radius:3px;-border-radius:3px;}
				#calendar_wrap .events{position:relative;}
					#calendar_wrap .events ul{background:#fff;border:1px solid white;color:white;display:none;font-size:12px;padding:15px;position:absolute;text-align:right;z-index:1000;width:200px;-moz-border-radius:3px;-khtml-border-radius:3px;-webkit-border-radius:3px;-border-radius:3px;list-style:none;color:#444444;-webkit-box-shadow:0px 8px 8px #333;}
					#calendar_wrap .events li{padding-bottom:5px;display:block;}
						#calendar_wrap .events li a{color:#555;text-align:justify;}
							#calendar_wrap .events li a.title{color:#222;font-weight:bold;}
		#calendar_wrap tfoot td{border:none;}
			#calendar_wrap tfoot td#prev{text-align:left;font-weight:bold;border:none;}
				#calendar_wrap tfoot td#prev a{border:none;}
			#calendar_wrap tfoot td#next{text-align:right;font-weight:bold;border:none;}
				#calendar_wrap tfoot td#next a{border:none;}

You need the following fields in your model:

'id' => Primary Key
'slug' => String Slug of your Evemt
'title' => String Event Title
'DAY(date) AS day' => Date/Datetime for the Event
'url' => (Optional) a full html url to any external links