A family cookbook could be a simple project such as a binder with just a few recipes to start or even a recipe box. These two ideas have the advantage the ability to start small and add to them in the future. The could even be started with the intention that when the collection of recipes is large enough to put them into a printed book.
On the other end of the scale would be a beautifully bound book with photos of the recipes and the stories behind these family favorites. Or do an enhanced ebook with videos about the recipes and their stories. Which ever direction you decide to take this project it is bound to bring up treasured memories and give new opportunities to make new memories all centered around families and good food.
Here are a few links for sites that can help you get a family cookbook put together.