Small example of singleton pattern applied to Memcache php class. Class was not writeln by be. But i think it will be usefull for somebody.

class clsMem extends Memcache {
	static private $m_objMem = NULL;
	static function getMem() {
		if (self::$m_objMem == NULL) {
			self::$m_objMem = new Memcache;
			// connect to the memcached on some 
                        //host __MEMHOST running it om __MEMPORT
			self::$m_objMem->connect('127.0.0.1', '11211') 
                        or die ("The memcached server");
		}
		return self::$m_objMem;
	}
}

Usage example:

$instance = clsMem::getMem();
// Do whatever you want now.