public static function getWeekDays()
    {
        static $weekdays = null;
        if ($weekdays == null) {
            $weekdays   = array();
            for ($i = 0; $i < 7; $i++) {
                $weekdays[$i] = strftime('%A', mktime(0, 0, 0, 1, $i, 2001));
            }
        }
        return $weekdays;
    }