$path = dirname(__FILE__);

$listing = array_filter(scandir($path), function($var) {

	// remove special directories '.' and '..' from listing
	if( preg_match('/^[.]{1,2}$/', $var) ) { return FALSE; }

	// remove files from listing
	if( !is_dir($var) ) { return FALSE; }

	return TRUE;
});

This is a little snippet of code I’ve been using a lot recently. This function will return all directories inside the path passed as $path. The functions utilizes the ability of Anonymous Functions, only available in PHP 5.3.0.