$helperToday = Mage::helper('today_special/data');
$arr = $helperToday->getCustomAttributeAndCategoryIdCollection();

017-12-13T05:01:48+00:00 ERR (3): Warning: include(): Failed opening 'Mage/Today/Helper/Data.php' for inclusion (include_path='/opt/bitnami/apps/magento/htdocs/app/code/local:/opt/bitnami/apps/magento/htdocs/app/code/community:/opt/bitnami/apps/magento/htdocs/app/code/core:/opt/bitnami/apps/magento/htdocs/lib:.:/opt/bitnami/php/lib/php:/opt/bitnami/frameworks/smarty/libs')  in /opt/bitnami/apps/magento/htdocs/lib/Varien/Autoload.php on line 94
2017-12-13T05:02:10+00:00 ERR (3): Warning: include(Mage/Today/Helper/Data.php): failed to open stream: No such file or directory  in /opt/bitnami/apps/magento/htdocs/lib/Varien/Autoload.php on line 94

<global>
        <helpers>
          <today_special>
              <class>Today_Special_Helper</class>
          </today_special>
        </helpers>
    </global>

<?php
class Today_Special_Helper_Data extends Mage_Core_Helper_Abstract
{

     public function getCustomAttributeAndCategoryIdCollection()
     {
        $todayStartOfDayDate  = Mage::app()->getLocale()->date()
                ->setTime('00:00:00')
                ->toString(Varien_Date::DATETIME_INTERNAL_FORMAT);

        $todayEndOfDayDate  = Mage::app()->getLocale()->date()
                ->setTime('23:59:59')
                ->toString(Varien_Date::DATETIME_INTERNAL_FORMAT);
        $bundledIds = array();
        $todayIds = array();
        $finalIds();

        $_productCollectionForTodaysSpecial = Mage::getModel('catalog/product')
                     ->getCollection()
                     ->joinTable('catalog_category_product', 'product_id=entity_id', array('category_id'=>'category_id'), null, 'left')
                     ->addAttributeToFilter('category_id', array('in' => array('finset' => '20')))
                     ->addAttributeToFilter(array(array('attribute' => 'today_special', 'eq' => '1')))
                     ->addAttributeToFilter('today_special_date', array('or'=> array(
                    0 => array('date' => true, 'to' => $todayEndOfDayDate),
                    1 => array('is' => new Zend_Db_Expr('null')))
                ), 'left')
                ->addAttributeToFilter('today_special_end_date', array('or'=> array(
                    0 => array('date' => true, 'from' => $todayStartOfDayDate),
                    1 => array('is' => new Zend_Db_Expr('null')))
                ), 'left')
                ->addAttributeToFilter(
                    array(
                        array('attribute' => 'today_special_date', 'is'=>new Zend_Db_Expr('not null')),
                        array('attribute' => 'today_special_end_date', 'is'=>new Zend_Db_Expr('not null')))
                    );

                $_productCollectionForBundledSpecial = Mage::getModel('catalog/product')
                     ->getCollection()
                     ->joinTable('catalog_category_product', 'product_id=entity_id', array('category_id'=>'category_id'), null, 'left')
                     ->addAttributeToFilter('category_id', array('in' => array('finset' => '22')))
                     ->addAttributeToFilter(array(array('attribute' => 'is_bundled', 'eq' => '1')))
                     ->addAttributeToFilter('show_bundled_start_date', array('or'=> array(
                    0 => array('date' => true, 'to' => $todayEndOfDayDate),
                    1 => array('is' => new Zend_Db_Expr('null')))
                ), 'left')
                ->addAttributeToFilter('show_bundled_enddate', array('or'=> array(
                    0 => array('date' => true, 'from' => $todayStartOfDayDate),
                    1 => array('is' => new Zend_Db_Expr('null')))
                ), 'left')
                ->addAttributeToFilter(
                    array(
                        array('attribute' => 'show_bundled_start_date', 'is'=>new Zend_Db_Expr('not null')),
                        array('attribute' => 'show_bundled_enddate', 'is'=>new Zend_Db_Expr('not null')))
                    );

            if(count($_productCollectionForTodaysSpecial)>0)
            {
                foreach ($_productCollectionForTodaysSpecial as $collection) {
                    foreach ($collection as $data){
                        $todayIds[] = $data['entity_id'];
                    }
                }
            }
            if(count($_productCollectionForBundledSpecial)>0)
            {
                foreach ($_productCollectionForBundledSpecial as $collection) {
                    foreach ($collection as $data){
                        $bundledIds[] = $data['entity_id'];
                    }
                }
            }

            if(!empty($bundledIds) && !empty($todayIds))
            {
                $finalIds = array_unique(array_merge($bundledIds,$todayIds));
            }
            else if(empty($bundledIds) && !empty($todayIds))
            {
                $finalIds = array_unique($todayIds);
            }
            else if(!empty($bundledIds) && empty($todayIds))
            {
                $finalIds =  array_unique($bundledIds);
            }
            else
            {
                $finalIds = array();
            }

        return $finalIds;
     }
}