Gingerbread Villae!
When I was in college, my roommate challenged me to a Gingerbread House contest. She wanted to create the Hogwarts Castle, and I, being a Classics major, decided to make an historically accurate Roman Villa.
As a teacher, I modified this activity into an educational tool where the students learn the rooms of the Roman house and then create their own villae.
Every year I try to add more details I want the students to focus on. This year, our textbook does a great job about teaching piscina, hortus, and cubiculum, and I make sure each house has an atrium as well as a triclinium in which 3 edible characters recline on a couch.