echo Request::factory('/blocks/menu/topmenu')->execute(); 

echo Request::factory('/blocks/sidebar/rightsidebar')->execute(); 

echo Request::factory('/blocks/widget/news')->execute(); 

Пример контроллера
<?php defined('SYSPATH') or die('No direct script access.');

class Controller_Blocks_Menu_Topmenu extends Controller {

   public function action_index()
   {   
        $content=View::factory('/blocks/menu/topmenu');
      $this->response->body($content); 
   }

} // End Menu (HMVC)

class Controller_Blocks_Menu extends Controller_Block

public function action_topmenu()
public function action_sidemenu()
public function action_languagemenu()

<?php defined('SYSPATH') or die('No direct script access.');

class Controller_Blocks extends Controller {

   public function before()
   {
     if ($this->request->is_initial()) 
     {
        //это не HMVC запрос
        throw new HTTP_Exception_403;
        // или что-то другое на ваше усмотрение.
     } 
   }
} 

Route::set('blocks', 'blocks/<controller>/<action>')
   ->defaults(array(
      'directory' => 'blocks',
   ));