The newsletter published by the Folk Song Society of Greater Boston (link given earlier in this thread) is a treasure trove of club and concert listings -- not just events sponsored by FSSGB, which tend to be mostly traditional music, but other music and dance venues in and near Boston. Go to their website and click the e-mail link for Suzanne Mrozak, who may be able to mail you a copy of their most recent newsletter so you can see the range of stuff available. (Unfortunately, the newsletter is not posted on the website.)

The sea chantey sing at the Press Room in Portsmouth, New Hampshire, is not a long drive from the Boston area (an hour, maybe). That gathering has many devoted followers here on the Mudcat. Try sending a PM to Jeri to get more details.

There's an Irish pub with regular sessions. PM Big Mick or Barry Finn for details.

Cuisine: seafood! Clams. Cod. Lobster rolls. Scallops. Wonderful Italian food on Boston's North End.
Sights: Thoreau's Walden Pond in Concord. Many historic sites relating to the Unpleasantness of 1776. Mount Auburn Cemetery in Cambridge (also home of Harvard U.), where many famous folks are buried and the birdwatching is world-class. The Isabella Stewart Gardner Museum and Museum of Fine Arts. The Boston Red Sox at Fenway Park (baseball season will still be in high gear in August). You won't lack for things to do; the hard thing will be choosing.