Many different styles of rallies, depending mostly on the organizer. Some groups organize most everything, have songfests, potluck dinners, etc. Some others may have catered meals, entertainment, golf matches or tours. A Social Hour (or two) in the late afternoon figures prominently in most rallies, either organized or spontaneous gatherings at somebody' campsite.
Our RV forum rallies tend to be simple in format and more spontaneous - just a bunch of friends getting together at a campground. Someone may suggest going out to dinner or visiting a local attraction, and folks join or not, as they wish. We generally gather for a Social (Happy) Hour to which folks may bring snacks and treats, and often decide to share a meal, potluck style. At smaller rallies somebody may make a pot of chili or chowder or BBQ or whatever and bring enough for everybody. An evening campfire is a feature that many of us enjoy.