Summer Fun with Family

We spent a week in Arizona with my husband's family.  With everyone spread out between New York, South Carolina, Florida, and California, it isn't easy to see each other as often as we'd like, so we began a family reunion tradition.  The kids played and swam while the adults drank adult beverages and played some serious water volleyball. Does your family have a reunion tradition?  Where are some of your favorite places in the country to vacation with large family groups?