Good sports bars in Boston?

I am a recent transplant to the Boston area - I'll be settling into the Metro West sprawl, but I'll probably be venturing into the city quite often over the weekends to generally explore and find stuff to do.  I was wondering if anybody familiar with the city could make some recommendations for sports bars - what are your favorite joints to pop in and have a couple while checking out the games?  I haven't spent a lot of time up here in the past, so I've never really gotten a feel for the city.  Any help or advice you could give would be appreciated.

NB: No need to tell me about Harpoon - I've known about them for years, and I adore their IPA.  Any other local brews I should check out?