check out the boston common, take the T (subway) to revere beach and get ice cream, the museum of fine arts (MFA) is great, walk along the charles, wander through quincy market, see the blue man group, explore any of the beautiful college campuses, walk down newbury st. for shopping, north end for great food (mike's pastry!!), etc
boston is a walkable city, but there's also the T if you're going farther, like revere. there are bars all over the place around where you're staying, and also a good cluster just north along the common. my friends and i liked estate, a karaoke/club atmosphere up on boylston. easy to walk to, but the green line also goes right there. have fun!