Conan O’Brien must be getting a bit homesick for Massachusetts. Last week, the Brookline-bred late-night host spoke to Casey Affleck about his hometown of Cambridge, which Affleck labeled “the slum, the gutter.” And then last night, Shrewsbury comedian Mike Birbiglia stopped by “Conan” to talk about O’Brien’s alma mater, Harvard, where Birbiglia’s interview apparently didn’t go so well. The comedian still remains determined to get the last laugh — if the students don’t get it at their own expense first.