What are good movies to watch for a get together?

I would say it depends on the group demographic. We'll usually put on O Brother Where Art Thou during family gatherings because a lot of the lines have become one liner inside jokes in my family (We're in a tight spot - Gopher Everett? - Mah Hair! etc...) If we have friends coming over with kids we'll put on one of the Toy Story movies to keep the kids occupied. Some other ones we'll put on are ones that everyone has seen, has parts to laugh at, but you can still carry on a conversation without worrying about missing major plot points like The Princess Bride, SpaceBalls (or any Mel Brooks movie) The Three Amigos, etc.