I needed a way to conditionally make fields required in the Laravel Validator. For example, 'What is your preferred PHP framework?' should only be required if 'Do you use a framework?' is set to '1'.
This is possible by extending the Validator class as I've described in this Gist (https://gist.github.com/4176954). You can then define validation rules such as the following:
$rules = array( 'uses_framework' => 'required', 'preferred_framework' => 'required_if_attribute:uses_framework,==,1' );