Mystic Seaport and Mystic Aquarium.
If you care enough to take it off your bucket list, you can go have a slice of pizza at "Mystic Pizza" made famous by the Julia Roberts movie of the same name. The funny thing is, I don't think they filmed any of the movie there (I could be wrong) and when I tried their pizza, it was average at best.
If you like wineries, you can try Stonington Vineyards. I wasn't too impressed with their operation and my wife and I were the only people who showed up for the tour that day. Still, it was an OK thing to do while we were in the area and we bought a few bottles of wine which I remember being pretty good.
No man is free who is not master of himself. --- Epictetus
Enjoy Yourself (It's Later Than You Think). --- Guy Lombardo