Usage:

use Silex\Application;
use Silex\Extension\TwigExtension;

require_once __DIR__.'/silex.phar';

$app = new Application();

$templates = array(
    'hello' => 'Hello {{ name }}',
);

$app->register(new TwigExtension(), array(
    'twig.templates'  => $templates,
    'twig.class_path' => '/path/to//Twig/lib',
));

$app->get('/{name}', function($name) use ($app) {
    return $app['twig']->render('hello', array('name' => $name));
});

$app->run();