There are plenty of great places to see in Boston! It's a great city to wander around. It's not too big, which is nice.
Here's a few things you can do:
Paul Revere's House
Bunker Hill Monument
Boston Tea Party Ship and Museum
Old North Church (where the 2 lanterns were hung)
Faneuil Hall Marketplace
USS Constitution (Old Ironsides)
One of my favorite things to do was to walk the Freedom Trail - which is a marked trail that goes through Boston, running through and past major locations involved in the Revolution. There are a few companies that offer walking (and I believe ride-on, as well) tours. One I know of is called Boston By Foot. It's a really cool tour - and if you don't feel like doing it, you can find the line on the street and just start walking!
And, of course, no visit to Boston would be complete (for a magician) without a trip to Hank Lee's Magic Factory! They moved locations a year or so ago, a bit further north of downtown Boston - but still close. Great people in there, so I would highly recommend a visit if you have the time.
If you need some tips or ideas - pm me. I can give you some more info.