Baltimore is known as Charm City, but even though you could spend a lot of your free time touring Baltimore, there are tons of great places to visit outside of Baltimore as well!
You could drive out on a Friday afternoon and have the better part of 2 days to enjoy the beach, boardwalk, and other fun things to do in Ocean City.
There are tons of hidden beaches in this area that are great for a secluded day on the water.
Deep Creek Lake and Garrett County is about 3.5 hours from Baltimore. It is far enough away to make you feel like you have traveled somewhere, but close enough for a weekend trip.
Swallow Falls State Park is home to Muddy Creek Falls- the highest waterfall in Maryland, as well as 3 other waterfalls.