For watching a movie in a theater,(this page should probably move from Viewings to Movies, but movies can also be shown at home... This should be moved to Theaters!!!)
Groups will typically meet at a restaurant, cafe or other nearby landmark before curtain call. Individuals are typically responsible for their own tickets.
Read the meetup carefully, sometimes the event is at a small venue and the tickets are sold online thru a service like The Stranger, Brown Paper Tickets, or Eventbrite, or the theater's own website.