WordPress custom menu display

Just a small example of how to build custom menu output in WordPress.

$menu_args		= array('menu' => 'Main menu', 'echo' => 0) ;
$menu_string	= wp_nav_menu($menu_args);
$xml	= new SimpleXMLElement($menu_string);
$out	= false;

foreach ($xml->ul[0] as $li) 
{
	$classes = array('current-page-ancestor', 'current-menu-item', 'current-menu-parent');
	if (strstr($li['class'], 'current-page-ancestor') || 
		strstr($li['class'], 'current-menu-item') || 
		strstr($li['class'], 'current-menu-parent')) 
	{
		$out = $li->ul;      
		$i = 0;
		if (isset($out->li) && !empty($out->li))
		{
			$out['id']		= 'sub_menu';
			$out['class']	= 'clear';
			foreach ($out->li as $li_sub) 
			{      
				if (!strstr($li_sub['class'], 'current-page-ancestor') && 
					!strstr($li_sub['class'], 'current-menu-item') && 
					!strstr($li_sub['class'], 'current-menu-parent')) 
				{
					unset($out->li[$i]->ul);
				}
				$i++;
			}
		}
		break;;
	}
}
if (!empty($out)) {
	 echo $out->asXML(); 
}