Best family fun deal around Boston?
The Davis Farmland in Sterling is a real steal. Kids get to see farm animals, use the playgrounds, go on ponyrides, do crafts, watch entertainment, join in a spray park, pick apples, and even do a real maze. Excellent value ... They even have picnic areas if you decide to bring your own food. Free parking, kiddie size bathrooms, and antiseptic gel stations all over, too.
Another wonderful place (west of the city) is Create-a-Cookie ClubHouse. Kids get to make their own cookies. For me that is an activity and snack — and pretty good tasting one at that — all in one.