This sounds pretty cool: the DC Preservation League is having a walking tour of Holmead Village, the area bounded by 13th, 14th, Spring and Park Road. Holmead Village, built from 1907-1911, is "the largest tract of houses to be built in Washington until that time and the development that instituted front-porch row-houses as the predominant free-standing house type in Washington for the next three decades."
The area even has a listserve!
Anyway, the event is Sunday at noon, starting from the Tivoli. It's free to Citywide Conference attendees, $15 for DCPL Members and $20 for Non-Members.
There's only 25 spots. "To make a reservation or for more information contact Amanda at DCPL by phone at 202.783.5144 or by email at firstname.lastname@example.org." Here's the whole ad (PDF).