Shelster - when are you going to Boston? The majority of the things to do in Boston are really outside, hopefully you'll have good weather.
I'd definitely recommend heading to Fanuel Hall marketplace. If you're looking for great Italian food, go over to the North End, great food EVERYWHERE you go, nice architecture and a beautiful little old church to see (North Church). The North End is within walking distance from Fanuel Hall if you were to go there first. Unfortunately, Fanuel Hall is alot more fun in the spring/summer, but nice to walk around anyway.
If you have some time, grab a taxi and head a little out of the way and see The Kennedy Museum. Check out Boston Public Library. If it's a good day outside, take a walk on the Freedom Trail (starts at the Boston Common, beautiful in spring/summer).
If you REALLY have some extra time - head North and go to Salem Massachusetts.
If you need to be inside because of the weather, check out the Aquarium (again, close proximity to the North End and Fanuel Hall). Maybe the Museum of Science or The Museum of Fine Arts might interest you.
While Boston may seem large, it really isn't...it's very much a walking city!!
If you have any thoughts as to what you may be interested in seeing or have questions about any specific places, let me know.
Oh...in case you're wondering - - this is where I'm from (don't live IN the city, but there lots!!)