Annapolis is a nice city to visit in a touristy kind of way. Nice if you want to walk out on the pier and look at a bunch of Yahts and things.
Also consider a tour of the Patomic River. There are numerous climbing areas along the river, and you might also get a chance to see some kayackers heading down some rapids.
Washington DC is not too far away, and if you take the rail in from Greenbelt its a pretty pleasant experience. There is the mall and the whole washington Monument. I once took a paddleboat out on the pool near the Jefferson Memorial, that was a nice day.
-percious