answer:Ask your host. He should be happy to tell you. Usually, there are yarmulkes provided for the men. Have your wife and daughter bring headscarves in their purses. Brace yourself for a possibly very long but interesting evening. Read up ahead of time on the history of the Passover and the traditional seder service. The book is called the Hagaddah, and there are dozens of different versions. Don’t bring food; there is the issue of keeping kosher and the traditional menu. Again, I would ask your host about kosher ****. Flowers or something useful, like pretty kitchen towels, would be appropriate. Or, simply enjoy the evening and send something afterwards.