What's considered a formal "date"?

So, I recently found out that my boyfriend's mom somewhat disapproves of our relationship because he doesn't take me on dates. But, I just realized, I don't really know what would be considered a formal date.

As of now, we mostly just hang out at each others' homes and play games. We go to the local gaming conventions together and sometimes the arcade. We also go to some of each others' school club meetings.
I'm not sure what else there's to do that'd we'd both enjoy and can afford.

None2015-11-27T19:58:25Z

A formal date would be going out into the public and probably just talking about life general. Maybe going for a walk in the park, hanging out at a restaurant or some ****.