St. Paddy's in Boston

Beer Luvvas,

I'm going to fly to Boston in the morning, and will be spending the evening in a Northern Boston suburb - Billerica.
I've heard that Boston is a great town for St. Paddy's, but I've never been to Massachusettes before, and I'm looking for recommendations. Barring any great tips in the comments, I'll do a search on The Beer Mapping Project.

Prost to St. Paddy's!