M.B.
Hi- You should definitely check out the Boston Central (bostoncentral.com) web site. They have many listings and links to events, etc. They will send you a weekly listing as well. For a day trip- two thoughts- Have you been to Davis Farms in Sterling MA.. it is fabulous. There are animals to pet and feed, face painting, a large play area, and also a water park. A day's worth of entertainment. You can bring a picnic and they also sell food. Also we enjoy going to Boston Common- riding the duck boats, using the frog pond, etc. but it can be pricey so we don't do it often. I also think a day at the beach is always good entertainment.
Enjoy! Best, M.