One of our favorite BBQ places near my parent's house
Capitol building (former capital of the United States also where George Washington retired, free to visit) Other historical buildings, shopping, and great Annapolitan food (such as Chick and Ruth's and Buddy's) There's also other fun bars and resturants.
Free museums! (Except for the Spy museum) Our personal favorites are the Natural History Museum and the National Portrait Gallery It is very easy to enter and travel around D.C. using the metro. New Carrolton Station is about 20 minutes from my parent's house Chinatown is one of Ryan's favorites with lots of delicious authentic food.
The Maryland Science Center is amazing, as are the other museums but they are not free. The Baltimore Inner Harbor is very pretty.