I wasn’t familiar with O’Brien’s Pub, which is a rather low-key establishment (maybe a lit up sign at night would help) located at the corner of Harvard Ave. and Cambridge Street in Allston. I was surprised and impressed to find an actual, decent-sized stage in the corner, with professional lighting and good sound. I see now that O’Brien’s is a serious rock venue. I assumed it was “just a bar” when I first heard that Division Day were playing there, and from the outside, one wouldn’t think otherwise. Well, it is a neighborhood bar, but it also regularly books local and national rock acts.