As a mother of 5, I am constantly trying to find cost effective ways to entertain and educate my children of various age groups.  We found that museums seem to keep everyone happy and the whinning to a minium. 

If you check online or by phone most museums have a free day or evening one day a week, and many offer a suggested donation.  We have gone to NYC's Metropolitain Museum of Art and paid $5 for the entire family, and the same for the Museum of Natural History, in NYC.  The MFA of Boston is free after 4pm on Weds. and is free all day on certain holidays, (Memorial Day etc.. ). Harvard's Museum of Natural History in Cambridge MA is free from 8:30am until 12pm on Sunday mornings. 

This really is worth looking into, culture can become quite costly for any family, and nobody has ever made us feel ashamed for only paying a small amount, for such a large family, so GO FOR IT!!!

Many museums now are allowing you to picnic indoors and provide a clean, safe way to eat your lunch packed from home!!  Plus, you don't need to take out a second mortgage just to feed your kiddos fast food that they only eat 1/4 of and are probably hungry, or thirsty 10 minutes later.