A friend called me with this question a half hour ago (she approached me because she knows I'm from Baltimore originally, and thought I might know something about Washington); in fact, I wasn't able to help her from my own knowledge, and the best place I know to get a reliable answer is you.
Her daughter is getting married in mid-April, in Greenbelt, MD (DC metro area), and she needs to know a good place to have a celebratory dinner the night before. Because the guests will be unfamiliar with the region, I thought it would be better to find a restaurant in the MD suburbs (like Chevy Chase, Bethesda, Silver Spring, etc.) to spare them the agony of driving in Washington proper. A private room that can accommodate twenty is needed. If you have any thoughts, or can suggest another information source I can go to for thoughts, I'd greatly appreciate it on behalf of my friend.