On the DotDev.co site they've posted an article from Talevski Igor about integrating Google's ReCaptcha with Laravel for use in verifying forms and protecting them against automated attacks.

Today i have task to create ReCaptcha on contact form with in a Laravel Web page and I like to share the process of making this possible.

He then walks you through the process of getting the configuration you'll need for your domain and using this package to easily integrate it with Laravel and its forms. He adds the routes for both the GET and POST requests along with the matching view and controller. He then uses the env helper function to get the ReCaptcha key from the configuration and places it in the form. He also adds the "g-recaptcha-response" variable to the required values rules and creates a simple Guzzle HTTP client to make the request back to Google to verify the result.