Fells Point is an historic area on the other side of the Inner Harbor. You can hope a water taxi for about ten bucks and get a great ride across the water. The water taxis run until fairly late in the evening and your one-time fee pays for a return ride home.
There are dozens of bars in Fells Point, from nightclubs to brew pubs to lounges to dives (my favorites). There's something for all of us lounge lizards. The fresh air and open water on the water taxi is a nice way to sober up, too!