Of the museums listed below, my favorite for kids is the MIT museum, which is very inexpensive and has LOTS of interactive exhibits. The Harvard museums tend to be a bit more stuffy, though they occassionally offer great kids programs. I've broken down the museums into art museums, then kid's museums.
Fogg Art Museum/Harvard University Address: 32 Quincy Street, Cambridge, (617) 495-9400 Website: artmuseums.harvard.edu Italian early Renaissance, British pre-Raphaelite, and 19th Century French art. Also Impressionist and post-Impressionist with some works by Picasso.
Isabella Stewart Gardner Museum Address: 280 The Fenway, Boston (617) 566-1401 Price: Adults - $10; College Students - $5, Children Under 18 Free Website: gardnermuseum.org Museum, Green Line Works by Titian, Boticelli, Raphael, Rembrandt, Degas, Matisse, and Sargent
Whistler Museum of Fine Arts Address: 465 Huntington Avenue, Boston (617) 267-9300 Website: mfa.org Largest art collection in New England, including ancient Egyptian, Nubian, and Near Eastern art. Also, major Monet collection.
Museum of the National Center of Afro-American Artists Address: 300 Walnut Ave., Boston, (617) 442-8614 Photography, paintings, sculpture and graphics.
SPORTS: Sports Museum One Fleet Center, North Station, 624-1235 www.sportsmuseum.org
KIDS MUSEUMS/ZOOS
Boston Children’s Museum Address 300 Congress Street, Boston, (617) 426-8855 Website: bostonkids.org Great interactive exhibits.
Franklin Park Zoo Address: 1 Franklin Park Road, Boston, (617) 541-LION Website: zoonewengland.com
Mapparium Address: Mary Baker Eddy Library, 200 Massachusetts Avenue, Boston (617) 450 – 3793 Website: marybakereddylibrary.org 30-foot diameter stained glass dome of the world in 1935
MIT Museum Age: Seems designed for 6-12. Lots of interactive exhibits for kids, including robots and computers. Also, several rooms with fun holograms. Also offers kids’ programming.