WordPress, get a sidebar as displayed on another page

iweb_get_dynamic_sidebar.php

<?php
/**
 * Get sidebar as displayed on another page
 * 
 * A dirty way to grab a sidebar as it's displayed on another page. Useful for
 * when widgets output a menu and you need to display the same menu on a post
 * type archive/single page.
 * 
 * @author Phil Wylie
 * @link http://goo.gl/qYf8H
 * @param string $dynamic_sidebar Name or ID of dynamic sidebar
 * @param int $page_id The page ID to get the sidebar from
 */
function iweb_get_dynamic_sidebar( $dynamic_sidebar, $page_id = null ) {	
	ob_start();
	
	if ( ! is_null( $page_id ) ) {
		global $post;
		
		$post = get_post( $page_id );
		
		dynamic_sidebar( $dynamic_sidebar );
		
		wp_reset_postdata();
	} else {
		dynamic_sidebar( $dynamic_sidebar );
	}
	
	$output = ob_get_clean();
	
	return $output;
}