Food is often the big thing here. If many people can bring their own favorite dishes, then you can share a little in their culture. [ That and Saber just really likes food, sorry Elsa. ] It is less of a burden on you to provide and everyone is pleased for the most part.

As for other things... you seem to have the basic gist of it down. Music, decorations, perhaps some games that could be played for those young at heart.