At the moment I'm doing project where I have FullCalendar and I have to do Recurring events. So this is my why how it's can be done. Hope this code help someone:)
I have next table in database:
CREATE TABLE IF NOT EXISTS `app_ext_calendar_events` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `users_id` int(11) NOT NULL,
  `name` varchar(255) NOT NULL,
  `description` text,
  `start_date` int(11) NOT NULL,
  `end_date` int(11) NOT NULL,
  `event_type` varchar(16) NOT NULL,
  `is_public` tinyint(1) DEFAULT NULL,
  `bg_color` varchar(16) DEFAULT NULL,
  `repeat_type` varchar(16) DEFAULT NULL,
  `repeat_interval` int(11) DEFAULT NULL,
  `repeat_days` varchar(16) DEFAULT NULL,
  `repeat_end` int(11) DEFAULT NULL,
  `repeat_limit` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `idx_users_id` (`users_id`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=18 ;
and I developed next php class to get events with repeat events:
<?php
class calendar
{
  static public function get_events($date_from, $date_to,$calendar_type)
  {
    global $app_user;
    $list = array();
    $events_query = db_query("select * from app_ext_calendar_events where FROM_UNIXTIME(start_date,'%Y-%m-%d')>='" . $date_from . "' and  FROM_UNIXTIME(end_date,'%Y-%m-%d')<='" . $date_to . "' and event_type='" . $calendar_type . "' and users_id='" . db_input($app_user['id']) . "'");
    while($events = db_fetch_array($events_query))
    {
      $list[] = $events; 
    }
    if(count($repeat_events_list = calendar::get_repeat_events($date_to,$calendar_type)))
    {
      $list = array_merge($list,$repeat_events_list);
    }
    return $list;
  }
  public static function weeks_dif($start, $end)
  {
    $year_start = date('Y',$start);
    $year_end = date('Y',$end);
    $week_start = date('W',$start); 
    $week_end = date('W',$end);
    $dif_years = $year_end - $year_start;
    $dif_weeks = $week_end - $week_start;
    if($dif_years==0 and $dif_weeks==0)
    {
      return 0;
    }
    elseif($dif_years==0 and $dif_weeks>0)
    {
      return $dif_weeks;
    }
    elseif($dif_years==1)
    {
      return (42-$week_start)+$week_end;
    }
    elseif($dif_years>1)
    {
      return (42-$week_start)+$week_end+(($dif_years-2)*42);
    }
  }
  public static function months_dif($start, $end)
  {
    // Assume YYYY-mm-dd - as is common MYSQL format
    $splitStart = explode('-', date('Y-n',$start));
    $splitEnd = explode('-', date('Y-n',$end));
    if (is_array($splitStart) && is_array($splitEnd)) 
    {
        $startYear = $splitStart[0];
        $startMonth = $splitStart[1];
        $endYear = $splitEnd[0];
        $endMonth = $splitEnd[1];
        $difYears = $endYear - $startYear;
        $difMonth = $endMonth - $startMonth;
        if (0 == $difYears && 0 == $difMonth) 
        { // month and year are same
            return 0;
        }
        else if (0 == $difYears && $difMonth > 0) 
        { // same year, dif months
            return $difMonth;
        }
        else if (1 == $difYears) 
        {
            $startToEnd = 13 - $startMonth; // months remaining in start year(13 to include final month
            return ($startToEnd + $endMonth); // above + end month date
        }
        else if ($difYears > 1) 
        {
            $startToEnd = 13 - $startMonth; // months remaining in start year 
            $yearsRemaing = $difYears - 2;  // minus the years of the start and the end year
            $remainingMonths = 12 * $yearsRemaing; // tally up remaining months
            $totalMonths = $startToEnd + $remainingMonths + $endMonth; // Monthsleft + full years in between + months of last year
            return $totalMonths;
        }
    }
    else 
    {
      return false;
    }
  }
  public static function get_repeat_events($date_to,$calendar_type)
  {
    global $app_user;
    //convert date to timestamp
    $date_to_timestamp = get_date_timestamp($date_to);
    $list = array();
    //get all events that already started (start_date<=date_to)      
    $events_query = db_query("select * from app_ext_calendar_events where length(repeat_type)>0 and FROM_UNIXTIME(start_date,'%Y-%m-%d')<='" . $date_to . "' and  event_type='" . $calendar_type . "' and users_id='" . db_input($app_user['id']) . "'");
    while($events = db_fetch_array($events_query))
    {
      $start_date = $events['start_date'];
      //set repeat end      
      $repeat_end = false;
      if($events['repeat_end']>0)
      {
        $repeat_end = $events['repeat_end'];
      } 
      //get repeat events by type                       
      switch($events['repeat_type'])
      {
        case 'daily': 
            //check repeat events day bay day       
            for($date = $start_date; $date<=$date_to_timestamp; $date+=86400)            
            {
              if($date>$start_date)
              {
                $dif = round(abs($date-$start_date)/86400);
                if($dif>0)
                {  
                  $event_obj = $events;                                                
                  $event_obj['start_date'] = strtotime('+' . $dif . ' day',$event_obj['start_date']);                                                          
                  $event_obj['end_date'] = strtotime('+' . $dif . ' day',$event_obj['end_date']);
                  if(calendar::check_repeat_event_dif($dif,$event_obj,$repeat_end))
                  {                
                    $list[] = $event_obj;                
                  }
                }
              }
            }                                                          
          break;
        case 'weekly':  
            //check repeat events day bay day    
            for($date = $start_date; $date<=$date_to_timestamp; $date+=86400)            
            {
              if($date>$start_date)
              {
                //find days dif
                $dif = round(abs($date-$start_date)/86400);
                //find week dif
                $week_dif = calendar::weeks_dif($start_date, $date);
                if($dif>0 and (in_array(date('N',$date),explode(',',$events['repeat_days']))))
                {  
                  $event_obj = $events;                                                
                  $event_obj['start_date'] = strtotime('+' . $dif . ' day',$event_obj['start_date']);                                                          
                  $event_obj['end_date'] = strtotime('+' . $dif . ' day',$event_obj['end_date']);
                  if(calendar::check_repeat_event_dif($week_dif,$event_obj,$repeat_end))
                  {                
                    $list[] = $event_obj;                
                  }
                }
              }
            }                       
          break;            
        case 'monthly':                        
            /**
             *in calendar we display 3 month in one view
             *so we have to check difference for each month
             */
             //check 1                                      
            $date_to_timestamp2 = strtotime('-2 month',$date_to_timestamp);
            $dif =  calendar::months_dif($start_date, $date_to_timestamp2);
            if($dif>0)
            {  
              $event_obj = $events;                                                
              $event_obj['start_date'] = strtotime('+' . $dif . ' month',$event_obj['start_date']);                                                          
              $event_obj['end_date'] = strtotime('+' . $dif . ' month',$event_obj['end_date']);
              if(calendar::check_repeat_event_dif($dif,$event_obj,$repeat_end))
              {                
                $list[] = $event_obj;                
              }
            }
            //check 2
            $date_to_timestamp1 = strtotime('-1 month',$date_to_timestamp);
            $dif =  calendar::months_dif($start_date, $date_to_timestamp1);
            if($dif>0)
            {  
              $event_obj = $events;                                                
              $event_obj['start_date'] = strtotime('+' . $dif . ' month',$event_obj['start_date']);                                                          
              $event_obj['end_date'] = strtotime('+' . $dif . ' month',$event_obj['end_date']);
              if(calendar::check_repeat_event_dif($dif,$event_obj,$repeat_end))
              {                
                $list[] = $event_obj;                
              }
            }
            //check 3
            $dif =  calendar::months_dif($start_date, $date_to_timestamp);
            if($dif>0)
            {     
              $event_obj = $events;                                             
              $event_obj['start_date'] = strtotime('+' . $dif . ' month',$event_obj['start_date']);                                                          
              $event_obj['end_date'] = strtotime('+' . $dif . ' month',$event_obj['end_date']);
              if(calendar::check_repeat_event_dif($dif,$event_obj,$repeat_end))
              {                                
                $list[] = $event_obj;
              }
            }
          break;
        case 'yearly':                        
            $dif =  date('Y',$date_to_timestamp)-date('Y',$start_date);
            if($dif>0)
            {             
              $events['start_date'] = strtotime('+' . $dif . ' year',$events['start_date']);                                                          
              $events['end_date'] = strtotime('+' . $dif . ' year',$events['end_date']);
              if(calendar::check_repeat_event_dif($dif,$events,$repeat_end))
              {
                $list[] = $events;
              }
            }                                                                                               
          break;
      }            
    }
    return $list;
  }
  static public function check_repeat_event_dif($dif,$events,$repeat_end)
  {
    $check = true;
    if($dif>0)
    {
      //check interval
      if($dif/$events['repeat_interval']!=floor($dif/$events['repeat_interval'])) $check=false;            
      //check repeat limit
      if($events['repeat_limit']>0)            
      if(floor($dif/$events['repeat_interval'])>$events['repeat_limit']) $check=false;
    }
    else
    {
      $check=false; 
    } 
    //check repeat end date            
    if($repeat_end>0)
    {
      if($repeat_end<$events['start_date'])
      {
         $check=false;
      }
    }
    return $check;
  }  
}
function get_events get all events + recurring events
in my way there are 4 type of recurring events: daily, weekly, monthly,yearly
+ there is repeat interval, repeat date end and repeat limit.
function get_repeat_events calculate difference for each type of event and include repeat event if exist.
note: function db_query() can be replace to myslq_query or something else
to prepare events to FullCalendar I'm using next code
$list = array();        
  foreach(calendar::get_events($_GET['start'],$_GET['end'],'personal') as $events)
  {
    $start = date('Y-m-d H:i',$events['start_date']);
    $end = date('Y-m-d H:i',$events['end_date']);
    $list[] = array('id' => $events['id'],
                  'title' => addslashes($events['name']),
                  'description' => str_replace(array("\n\r","\n","\r"),'<br>',$events['description']),
                  'start' => str_replace(' 00:00','',$start),
                  'end' => str_replace(' 00:00','',$end),
                  'color'=> $events['bg_color'],                      
                  'allDay'=>(strstr($start,'00:00') and strstr($end,'00:00')),
                  'url' => url_for('ext/calendar/personal_form','id=' . $events['id'])                      
                  );      
  }
  echo json_encode($list);