Two of the bigger university-associated stations are not really college radio at all. WBUR-FM (90.9) at Boston University and WUMB- FM (91.9) at the University of Massachusetts at Boston are professionally run public-radio stations. WBUR focuses on news and talk; WUMB specializes in folk and acoustic music.
Tufts's WMFO-FM (91.5), another community station, remains largely free-form, which means eclectic mixes of indie rock, jazz, and experimental sounds can show up on most of the Medford-based station's shows. A few exceptions (including two blocks, Tuesdays and Wednesdays, 9-11 a.m.) program roots and blues, and hardcore punk rules the "Headbanger's Ball" (Tuesdays, 1-3 p.m.). But each DJ has his or her own style, so keep tuning in till you find a mix you like.
There's not room to list every station, such as Salem State's WMWM-FM (91.7) and UMass-North Dartmouth's WSMU-FM (91.1). But keep in mind: If there's a college near you, it probably has a station. A cruise around the bottom of the dial could change your listening habits.