I don't see any in MD or DC but a couple in VA.  See the screenshot below from the fitting site.

There are a couple upcoming in the PA, NY area, but nothing in DC.  Most of the fitting days were conducted in the spring time.  Here is the link to the events.  It may be difficult to see, but you can filter the state, city and type of event by clicking on the right (in the black next to state, city, etc).  http://www.titleist.com/teamtitleist/team-titleist/f/6/p/25875/116096.aspx#116096

We do have several Advanced Fitters in your area - Larry Bleich at The Fitting Studio at Westfield in Clifton, VA - his number is 703-988-0187, Roger Hatcher at the 1757 Club in Dulles, VA - his number is: 703-444-0901.  Jerry Donahue is at GTT Game Improvement  in Warrenton, VA - 540-349-9761. 

Also, the University of Maryland GC has trial sets and you can play the course and try out a set.

Unfortunately there doesn't seem to be a lot of demos in the NOVA area.  A lot of them are early in the spring, which I think is unfortunate.  Our spring weather is so unpredictable it makes a demo day very iffy.  I went to one last spring, but the wind was so strong, it was essentially useless.  The wind was blowing the ball so far off course you had no idea about ball flight.  I wish more courses would hold demo days throughout the summer.