A beautiful hack to extend Rails to allow custom actions for a controller instance & helpers for thew view.

Rails3-ExtendController

  def self.extended(controller)
    controller.extend(ControllerMethods)
    controller._helpers.module_eval { include HelperMethods }
    
    existing_actions = controller.action_methods + ControllerMethods.public_instance_methods(true)
    controller.class.class_eval do
      cattr_accessor :actions_to_use
      
      def self.override_action_methods(actions=[])
        self.actions_to_use = actions
      end
      
      def self.action_methods
        self.actions_to_use || @action_methods
      end
    end
    controller.class.override_action_methods(existing_actions)
  end

Use: 
 In before_filter on controller:
    load File.join(file_root,'content_methods.rb') unless Object.const_defined?(@client_domain.namespace)
    self.extend(@client_domain.namespace.constantize)