Integrating qaptcha with gravity forms?

That looks pretty neat. One way to do it would be to make the submit button conditionally appear based on the result of that QapTcha - I'm not sure what sort of value that jQuery plugin provides, but basically, enable conditional logic on the Advanced tab of the form settings, and make it condition true when this plugin returns true. There might be a limitation on the drop downs there, since this plugin is not integrated with Gravity Forms.

You could also add this to your form and disable the submit button yourself, all within jQuery.

I'm not sure if there is an easy way to do it. I have not see this jQuery plugin before today and don't know of anyone who has integrated it with Gravity Forms.