Unfortunately, the best part of Boston no longer exists. The Harpoon people used to have a free beer "tasting" where you basically came and drank beer. A lot of beer. And it was the good expensive lines also.
But now they got too popular, so there's a tour which costs 5 dollars you have to go on, and then you don't get nearly as much beer.
Sam Adams also has a tour for 2 dollars, and you drink a couple beers, but not the cool ones.