diff --git a/plugins/calendar/calendar.js b/plugins/calendar/calendar.js
index 1ef5894e..674dc5d2 100644
--- a/plugins/calendar/calendar.js
+++ b/plugins/calendar/calendar.js
@@ -45,20 +45,6 @@ window.rcmail && rcmail.addEventListener('init', function(evt) {
     // private vars
     var day_clicked = 0;
     var ignore_click = false;
-    
-    // data loader
-    var load_events = function(calendar, start, end, callback) {
-      $.ajax({
-        url: "./?_task=calendar&_action=plugin.load_events",
-        dataType: 'json',
-        data: {
-          source: calendar,
-          start: Math.round(start.getTime() / 1000),
-          end: Math.round(end.getTime() / 1000)
-        },
-        success: callback
-      });
-    };
 
     // event details dialog (show only)
     var event_show_dialog = function(event) {
@@ -438,7 +424,7 @@ window.rcmail && rcmail.addEventListener('init', function(evt) {
     for (var id in rcmail.env.calendars) {
       cal = rcmail.env.calendars[id];
       this.calendars[id] = $.extend({
-        events: function(start, end, callback) { load_events(id, start, end, callback); },
+        url: "./?_task=calendar&_action=plugin.load_events&source="+escape(id),
         editable: !cal.readonly,
         className: 'fc-event-cal-'+id,
         id: id
@@ -455,8 +441,9 @@ window.rcmail && rcmail.addEventListener('init', function(evt) {
           }
         }).data('id', id);
         $(li).click(function(e){
+          var id = $(this).data('id');
           rcmail.select_folder(id, me.selected_calendar, 'rcmlical');
-          me.selected_calendar = $(this).data('id');
+          me.selected_calendar = id;
         }).data('id', id);
       }
       
diff --git a/plugins/calendar/calendar.php b/plugins/calendar/calendar.php
index 61cf97ff..a4342a82 100644
--- a/plugins/calendar/calendar.php
+++ b/plugins/calendar/calendar.php
@@ -521,7 +521,9 @@ class calendar extends rcube_plugin
    */
   public static function parse_alaram_value($val)
   {
-    if (preg_match('/([+-])(\d+)([HMD])/', $val, $m))
+    if ($val[0] == '@')
+      return array(substr($val, 1));
+    else if (preg_match('/([+-])(\d+)([HMD])/', $val, $m))
       return array($m[2], $m[1].$m[3]);
     
     return false;
diff --git a/plugins/calendar/drivers/calendar_driver.php b/plugins/calendar/drivers/calendar_driver.php
index c479adfb..db0592e1 100644
--- a/plugins/calendar/drivers/calendar_driver.php
+++ b/plugins/calendar/drivers/calendar_driver.php
@@ -131,10 +131,26 @@ abstract class calendar_driver
    *
    * @param  integer Current time (unix timestamp)
    * @param  mixed   List of calendar IDs to show alarms for (either as array or comma-separated string)
-   * @return array A list of alarms
+   * @return array A list of alarms, each encoded as hash array:
+   *         id: Event identifier
+   *        uid: Unique identifier of this event
+   *   calendar: Calendar identifier to add event to (optional)
+   *      start: Event start date/time as unix timestamp
+   *        end: Event end date/time as unix timestamp
+   *     allday: Boolean flag if this is an all-day event
+   *      title: Event title/summary
+   *   location: Location string
    */
   abstract function pending_alarms($time, $calendars = null);
 
+  /**
+   * (User) feedback after showing an alarm notification
+   * This should mark the alarm as 'shown' or snooze it for the given amount of time
+   *
+   * @param  string  Event identifier
+   * @param  integer Suspend the alarm for this number of seconds
+   */
+  abstract function confirm_alarm($event_id, $snooze = 0);
 
   /**
    * Save an attachment related to the given event
diff --git a/plugins/calendar/drivers/database/database_driver.php b/plugins/calendar/drivers/database/database_driver.php
index 812070d8..08d83e4f 100644
--- a/plugins/calendar/drivers/database/database_driver.php
+++ b/plugins/calendar/drivers/database/database_driver.php
@@ -139,8 +139,8 @@ class database_driver extends calendar_driver
       $event = $this->_save_preprocess($event);
       $query = $this->rc->db->query(sprintf(
         "INSERT INTO " . $this->db_events . "
-         (calendar_id, created, changed, uid, start, end, all_day, recurrence, title, description, location, categories, free_busy, priority, alarms)
-         VALUES (?, %s, %s, ?, %s, %s, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+         (calendar_id, created, changed, uid, start, end, all_day, recurrence, title, description, location, categories, free_busy, priority, alarms, notifyat)
+         VALUES (?, %s, %s, ?, %s, %s, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
           $this->rc->db->now(),
           $this->rc->db->now(),
           $this->rc->db->fromunixtime($event['start']),
@@ -156,7 +156,8 @@ class database_driver extends calendar_driver
         strval($event['categories']),
         intval($event['free_busy']),
         intval($event['priority']),
-        $event['alarms']
+        $event['alarms'],
+        $event['notifyat']
       );
       return $this->rc->db->insert_id($this->sequence_events);
     }
@@ -176,7 +177,7 @@ class database_driver extends calendar_driver
       $event = $this->_save_preprocess($event);
       $query = $this->rc->db->query(sprintf(
         "UPDATE " . $this->db_events . "
-         SET   changed=%s, start=%s, end=%s, all_day=?, recurrence=?, title=?, description=?, location=?, categories=?, free_busy=?, priority=?, alarms=?
+         SET   changed=%s, start=%s, end=%s, all_day=?, recurrence=?, title=?, description=?, location=?, categories=?, free_busy=?, priority=?, alarms=?, notifyat=?
          WHERE event_id=?
          AND   calendar_id IN (" . $this->calendar_ids . ")",
           $this->rc->db->now(),
@@ -192,6 +193,7 @@ class database_driver extends calendar_driver
         intval($event['free_busy']),
         intval($event['priority']),
         $event['alarms'],
+        $event['notifyat'],
         $event['id']
       );
       return $this->rc->db->affected_rows($query);
@@ -220,11 +222,38 @@ class database_driver extends calendar_driver
     }
     else if (is_string($event['recurrence']))
       $rrule = $event['recurrence'];
-      
+    
     $event['recurrence'] = rtrim($rrule, ';');
     $event['free_busy'] = intval($this->free_busy_map[strtolower($event['free_busy'])]);
     $event['allday'] = $event['allday'] ? 1 : 0;
     
+    // compute absolute time to notify the user
+    if ($event['alarms']) {
+      list($action, $trigger) = explode(':', $event['alarms']);
+      $notify = calendar::parse_alaram_value($trigger);
+      if (!empty($notify[1])){  // offset
+        $mult = 1;
+        switch ($notify[1]) {
+          case '-M': $mult =    -60; break;
+          case '+M': $mult =     60; break;
+          case '-H': $mult =  -3600; break;
+          case '+H': $mult =   3600; break;
+          case '-D': $mult = -86400; break;
+          case '+D': $mult =  86400; break;
+        }
+        $offset = $notify[0] * $mult;
+        $refdate = $mult > 0 ? $event['end'] : $event['start'];
+        $notify_at = $refdate + $offset;
+      }
+      else {  // absolute timestamp
+        $notify_at = $notify[0];
+      }
+      
+      $event['notifyat'] = date('Y-m-d H:i:s', $notify_at);
+    }
+    else
+      $event['notifyat'] = null;
+    
     return $event;
   }
 
@@ -237,9 +266,10 @@ class database_driver extends calendar_driver
   public function move_event($event)
   {
     if (!empty($this->calendars)) {
+      $event = $this->_save_preprocess($event + (array)$this->get_event($event['id']));
       $query = $this->rc->db->query(sprintf(
         "UPDATE " . $this->db_events . "
-         SET   changed=%s, start=%s, end=%s, all_day=?
+         SET   changed=%s, start=%s, end=%s, all_day=?, notifyat=?
          WHERE event_id=?
          AND calendar_id IN (" . $this->calendar_ids . ")",
           $this->rc->db->now(),
@@ -247,6 +277,7 @@ class database_driver extends calendar_driver
           $this->rc->db->fromunixtime($event['end'])
         ),
         $event['allday'] ? 1 : 0,
+        $event['notifyat'],
         $event['id']
       );
       return $this->rc->db->affected_rows($query);
@@ -264,15 +295,17 @@ class database_driver extends calendar_driver
   public function resize_event($event)
   {
     if (!empty($this->calendars)) {
+      $event = $this->_save_preprocess($event + (array)$this->get_event($event['id']));
       $query = $this->rc->db->query(sprintf(
         "UPDATE " . $this->db_events . "
-         SET   changed=%s, start=%s, end=%s
+         SET   changed=%s, start=%s, end=%s, notifyat=?
          WHERE event_id=?
          AND calendar_id IN (" . $this->calendar_ids . ")",
           $this->rc->db->now(),
           $this->rc->db->fromunixtime($event['start']),
           $this->rc->db->fromunixtime($event['end'])
         ),
+        $event['notifyat'],
         $event['id']
       );
       return $this->rc->db->affected_rows($query);
@@ -302,6 +335,27 @@ class database_driver extends calendar_driver
     return false;
   }
 
+  /**
+   * Return data of a specific event
+   * @param string Event ID
+   * @return array Hash array with event properties
+   */
+  public function get_event($id)
+  {
+    $result = $this->rc->db->query(sprintf(
+      "SELECT * FROM " . $this->db_events . "
+       WHERE calendar_id IN (%s)
+       AND event_id=?",
+       $this->calendar_ids
+      ),
+      $id);
+
+    if ($result && ($event = $this->rc->db->fetch_assoc($result)))
+      return $this->_read_postprocess($event);
+
+    return false;
+  }
+
   /**
    * Get event data
    *
@@ -315,48 +369,57 @@ class database_driver extends calendar_driver
       $calendars = explode(',', $calendars);
     
     // only allow to select from calendars of this use
-    $calendars = array_intersect($calendars, array_keys($this->calendars));
+    $calendar_ids = array_intersect($calendars, array_keys($this->calendars));
+    array_walk($calendar_ids, array($this->rc->db, 'quote'));
     
     $events = array();
-    $free_busy_map = array_flip($this->free_busy_map);
-    
-    if (!empty($calendars)) {
+    if (!empty($calendar_ids)) {
       $result = $this->rc->db->query(sprintf(
         "SELECT * FROM " . $this->db_events . "
          WHERE calendar_id IN (%s)
          AND start <= %s AND end >= %s",
-         $this->calendar_ids,
+         join(',', $calendar_ids),
          $this->rc->db->fromunixtime($end),
          $this->rc->db->fromunixtime($start)
        ));
 
       while ($result && ($event = $this->rc->db->fetch_assoc($result))) {
-        $event['id'] = $event['event_id'];
-        $event['start'] = strtotime($event['start']);
-        $event['end'] = strtotime($event['end']);
-        $event['free_busy'] = $free_busy_map[$event['free_busy']];
-        $event['calendar'] = $event['calendar_id'];
-        
-        // parse recurrence rule
-        if ($event['recurrence'] && preg_match_all('/([A-Z]+)=([^;]+);?/', $event['recurrence'], $m, PREG_SET_ORDER)) {
-          $event['recurrence'] = array();
-          foreach ($m as $rr) {
-            if (is_numeric($rr[2]))
-              $rr[2] = intval($rr[2]);
-            else if ($rr[1] == 'UNTIL')
-              $rr[2] = strtotime($rr[2]);
-            $event['recurrence'][$rr[1]] = $rr[2];
-          }
-        }
-        
-        unset($event['event_id'], $event['calendar_id']);
-        $events[] = $event;
+        $events[] = $this->_read_postprocess($event);
       }
     }
     
     return $events;
   }
 
+  /**
+   * Convert sql record into a rcube style event object
+   */
+  private function _read_postprocess($event)
+  {
+    $free_busy_map = array_flip($this->free_busy_map);
+    
+    $event['id'] = $event['event_id'];
+    $event['start'] = strtotime($event['start']);
+    $event['end'] = strtotime($event['end']);
+    $event['free_busy'] = $free_busy_map[$event['free_busy']];
+    $event['calendar'] = $event['calendar_id'];
+    
+    // parse recurrence rule
+    if ($event['recurrence'] && preg_match_all('/([A-Z]+)=([^;]+);?/', $event['recurrence'], $m, PREG_SET_ORDER)) {
+      $event['recurrence'] = array();
+      foreach ($m as $rr) {
+        if (is_numeric($rr[2]))
+          $rr[2] = intval($rr[2]);
+        else if ($rr[1] == 'UNTIL')
+          $rr[2] = strtotime($rr[2]);
+        $event['recurrence'][$rr[1]] = $rr[2];
+      }
+    }
+    
+    unset($event['event_id'], $event['calendar_id']);
+    return $event;
+  }
+
   /**
    * Search events
    *
@@ -374,14 +437,63 @@ class database_driver extends calendar_driver
    */
   public function pending_alarms($time, $calendars = null)
   {
-    // TBD.
-    return array();
+    if (empty($calendars))
+      $calendars = array_keys($this->calendars);
+    else if (is_string($calendars))
+      $calendars = explode(',', $calendars);
+    
+    // only allow to select from calendars of this use
+    $calendar_ids = array_intersect($calendars, array_keys($this->calendars));
+    array_walk($calendar_ids, array($this->rc->db, 'quote'));
+    
+    $alarms = array();
+    if (!empty($calendar_ids)) {
+      $result = $this->rc->db->query(sprintf(
+        "SELECT * FROM " . $this->db_events . "
+         WHERE calendar_id IN (%s)
+         AND notifyat <= %s",
+         join(',', $calendar_ids),
+         $this->rc->db->fromunixtime($time)
+       ));
+
+      while ($result && ($event = $this->rc->db->fetch_assoc($result)))
+        $alarms[] = $this->_read_postprocess($event);
+    }
+
+    return $alarms;
+  }
+
+  /**
+   * Feedback after showing/sending an alarm notification
+   *
+   * @see Driver:confirm_alarm()
+   */
+  public function confirm_alarm($event_id, $snooze = 0)
+  {
+    // set new notifyat time
+    if ($snooze > 0) {
+      $event = $this->get_event($event_id);
+      $notify_at = date('Y-m-d H:i:s', strtotime($event['notifyat']) + $snooze);
+    }
+    else  // unset notifyat value
+      $notify_at = null;
+    
+    $query = $this->rc->db->query(sprintf(
+      "UPDATE " . $this->db_events . "
+       SET   changed=%s, notifyat=?
+       WHERE event_id=?
+       AND calendar_id IN (" . $this->calendar_ids . ")",
+        $this->rc->db->now()),
+      $notify_at,
+      $event_id
+    );
+    return $this->rc->db->affected_rows($query);
   }
 
   /**
    * Save an attachment related to the given event
    */
-  function add_attachment($attachment, $event_id)
+  public function add_attachment($attachment, $event_id)
   {
     // TBD.
     return false;
@@ -390,7 +502,7 @@ class database_driver extends calendar_driver
   /**
    * Remove a specific attachment from the given event
    */
-  function remove_attachment($attachment, $event_id)
+  public function remove_attachment($attachment, $event_id)
   {
     // TBD.
     return false;
diff --git a/plugins/calendar/drivers/database/sql/mysql.sql b/plugins/calendar/drivers/database/sql/mysql.sql
index 31fb07d8..5956ffdb 100644
--- a/plugins/calendar/drivers/database/sql/mysql.sql
+++ b/plugins/calendar/drivers/database/sql/mysql.sql
@@ -41,6 +41,7 @@ CREATE TABLE `events` (
   `priority` tinyint(1) NOT NULL DEFAULT '1',
   `alarms` varchar(255) DEFAULT NULL,
   `attendees` text DEFAULT NULL,
+  `notifyat` datetime NOT NULL DEFAULT '1000-01-01 00:00:00',
   PRIMARY KEY(`event_id`),
   CONSTRAINT `fk_events_calendar_id` FOREIGN KEY (`calendar_id`)
     REFERENCES `calendars`(`calendar_id`) ON DELETE CASCADE ON UPDATE CASCADE
diff --git a/plugins/calendar/drivers/database/sql/postgresql.sql b/plugins/calendar/drivers/database/sql/postgresql.sql
index 58681368..5b75e545 100644
--- a/plugins/calendar/drivers/database/sql/postgresql.sql
+++ b/plugins/calendar/drivers/database/sql/postgresql.sql
@@ -55,7 +55,8 @@ CREATE TABLE events (
     free_busy smallint NOT NULL DEFAULT 0,
     priority smallint NOT NULL DEFAULT 1,
     alarms varchar(255) DEFAULT NULL,
-    attendees text DEFAULT NULL
+    attendees text DEFAULT NULL,
+    notifyat timestamp without time zone DEFAULT now() NOT NULL
     PRIMARY KEY (event_id)
 );
 
diff --git a/plugins/calendar/drivers/database/sql/sqlite.sql b/plugins/calendar/drivers/database/sql/sqlite.sql
index 22ef23d2..a102f279 100644
--- a/plugins/calendar/drivers/database/sql/sqlite.sql
+++ b/plugins/calendar/drivers/database/sql/sqlite.sql
@@ -41,6 +41,7 @@ CREATE TABLE events (
   priority tinyint(1) NOT NULL default '1',
   alarms varchar(255) default NULL,
   attendees text default NULL,
+  notifyat datetime NOT NULL default '1000-01-01 00:00:00',
   CONSTRAINT fk_events_calendar_id FOREIGN KEY (calendar_id)
     REFERENCES calendars(calendar_id)
 );
diff --git a/plugins/calendar/drivers/kolab/kolab_driver.php b/plugins/calendar/drivers/kolab/kolab_driver.php
index 3edcf6f9..1a23da31 100644
--- a/plugins/calendar/drivers/kolab/kolab_driver.php
+++ b/plugins/calendar/drivers/kolab/kolab_driver.php
@@ -233,6 +233,17 @@ class kolab_driver extends calendar_driver
     return array();
   }
 
+  /**
+   * Feedback after showing/sending an alarm notification
+   *
+   * @see Driver:confirm_alarm()
+   */
+  public function confirm_alarm($event_id, $snooze = 0)
+  {
+    // TBD.
+    return false;
+  }
+  
   /**
    * Save an attachment related to the given event
    */