As you've no doubt heard, the National Center for Education Statistics has concluded that students score lower on proficiency tests in U.S. history than any other subject. That's all the more reason to take them on trips where they might get excited about what happened long ago. Meanwhile, if you'd like to sneak a little history into your kids' summer vacation, the new book Boston and the State of Massachusetts: Cool Stuff Every Kid Should Know by Kate Boehm Jerome (Arcadia Publishing, $9.99) might be a good place to start. The slim volume is geared toward ages 7 to 11 and mixes an upbeat style and colorful illustrations with lots of fun facts. Most adults probably don't know how many chests of tea the patriots dumped into Boston Harbor in 1773 (342). But most of us might recall the height of Fenway Park's Green Monster, right? (It's 37 feet). The fun series also covers a number of other cities, including Austin, San Antonio, Chicago, and Philadelphia.