My mom's family is from Boston so I've spent a lot of time there. Everyone has done a pretty good job giving you the highlites, enjoy the lobster if you're so inclined and check out Chestnut Hill/Boston College if you have time, gorgeous campus.
You'll enjoy yourself but as someone said earlier check out Boston Common and look for my favourite spot in Beantown:
http://farm2.static.flickr.com/1111/...6f16435774.jpg
Long shot but did anyone ever read Make Way for Ducklings?
http://en.wikipedia.org/wiki/Make_Way_for_Ducklings