Mystic has a pretty wide selection of stuff. Places to walk around. Old Mystic village for some fun shops. As well as the Mystix Aquarium and the Seaport Museum. The Submarine Force Museum is in nearby Groton if you are interested in Submarine history as well as being able to tour the Nautilus, the first nuclear powered submarine. And the casinos (Mohegan Sun and Foxwoods) are also a short drive away.