Hmmm... I just saw a musician-acquaintance of mine from Boston last weekend, when she was visiting this area. As we were chatting, I asked her what the folk-music "scene" was like there, and she said it was very vibrant and busy. I'll see if I can contact her for details!

Also, check out the community calendar posted by WUMB folk-music radio, 91.9 FM, Boston: http://www.wumb.org/commcal.html (right now they have April's schedule, but it should be updated for May long before your trip). There's also a page of "Area Venue Links" on /www.wumb.org/.

Other radio stations with folk-music programming may have helpful info. Check this page for contacts: http://www.music-for-robin.org/radio.htm

(see the link from that page to WGBH's Celtic Calendar, too!)