We used to have an annual event that was essentially an outdoor service (held in a covered pavilion, because the weather didn't always play nicely) followed by a bring-and-share meal and games. We stopped doing it because people would come for the service but not stay around, and it seemed like a waste of money to pay several hundred dollars to rent a nice location if all we were going to do was have a regular service and then leave.
At my previous church, they rented out a community park and everyone brought a pot luck dish, but also, certain groups/committees were in charge of things (ice, chicken, games, etc). It was a huge event.
At my current church when I first started attending, they did a picnic at a park, but I only attended one time. It was too much work for people who were older, so they stopped doing it.