What to do for 4 hours with someone I barely know?

So we're going on a sort-of date, unofficially! And I really like him, but we're spending 4 hours together today (I know because we both have to be somewhere at a certain time) and we've already done all the 'getting to know' each other stuff, like questions about hobbies and interests. I'm scared that it's going to be awkward. Especially since I'm nervous as hell! Any tips?