If your kid is into trains, the Connecticut Cellar Savers Fire Museum is a definite must-see. It's in Portland, Conn. and features an entire room of working model trains. Best of all it's free (and there's a bathroom on the premises). You can easily spend an hour there, but probably not much longer.
The man who sits behind the counter is really nice, which is a rarity for the area. Last time we went, he told Junior to hug me and then said, "You only get one mom, so hug her and tell her thanks!"
Melt my heart.
Bonus: Sometimes the next door neighbor's chickens and hens wander the parking lot and the kids can kill another 15 minutes trying to catch them.
It never stops raining fun in this state. Am I right?