JavaScript

/**
 * Add event listener
 */
function addEvent(el, type, fn) {
	if (window.addEventListener) {
		addEvent = function(el, type, fn) {
			el.addEventListener(type, fn, false);
		}
	} else if (window.attachEvent) {
		addEvent = function(el, type, fn) {
			var f = function() {
				fn.call(el, window.event);
			}
			el.attachEvent('on' + type, f);
		}
	}
	return addEvent(el,type,fn);
}

Ruby

class BlankSlate
  instance_methods.each { |m| undef_method m unless m =~ /^__/ }
end

class Proxy < BlankSlate
  def initialize(obj)
    @obj = obj
  end

  def method_missing(sym, *args, &block)
    puts "Sending #{sym}(#{args.join(',')}) to obj"
    @obj.__send__(sym, *args, &block)
  end
end

PHP

class Zend_Memory
{
    public static function factory($backend, $backendOptions = array())
    {
        if (strcasecmp($backend, 'none') == 0) {
            return new Zend_Memory_Manager();
        }

        // because lowercase will fail
        $backend = @ucfirst(strtolower($backend));

        if (!in_array($backend, Zend_Cache::$availableBackends)) {
            throw new Zend_Memory_Exception("Incorrect backend ($backend)");
        }

        $backendClass = 'Zend_Cache_Backend_' . $backend;

        require_once str_replace('_', DIRECTORY_SEPARATOR, $backendClass) . '.php';

        $backendObject = new $backendClass($backendOptions);

        return new Zend_Memory_Manager($backendObject);
    }
}