We have a family reunion every year. We usually have games for the kids, but we also have some activities for the older family members. One year, we have everyone bring a baby picture. We mounted them on a display board and had a "guess who" contest. We usually have bingo, because that is popular with our crowd. Probably the most popular thing that we have done is to have everyone bring two or three of their favorite recipes to the reunion with a short (1-2 sentences) explination of why the recipe is a favorite. Then, I took all of them and typed them and put them in 3 ring binders so that everyone would have a "family" cookbook.
The grossest thing we ever did was when my 80+ grandmother started a guess-how-many-flies-will-land-on-the-flystrip contest. She charged everyone $1 per guess with the winner getting the money. My family is full of gamblers who will be on ANYTHHING. I would not suggest this, but it is a funny memory that I have of my grandmother.