Fort McHenry! Take the water taxi across to it so you can have the Francis Scott Key angle of coming in thinking about bombs bursting in air and the flag still there. If you can time the tour right, you can help fold the giant flag when they take it down for the night. If the Orioles are in town, consider a baseball game.... Camden yards is the coolest MLB park of all, imo. One side is an old train station. Eat crabs of course.