A couple of fun links

Not sure if anyone else saw these but there are two galleries of historical photos on DDOT's website including these:

http://ddot.dc.gov/ddot/cwp/view,a,1250,q,641406.asp

http://ddot.dc.gov/ddot/cwp/view,a,1250,q,639600,ddotNav,%7C32399%7C.asp

And I could be mistaken but I believe in this photo you can see the existing Tenleytown library under construction!

http://ddot.dc.gov/ddot/cwp/view,a,1250,q,639607,ddotNav,%7C32399%7C.asp

And finally here is a fun website I found a few months ago that tries to calculate the walkability of a neighborhood:

http://www.walkscore.com/

It seems to strictly measure retail within walking distance and doesn't attempt to ascertain how unfriendly a neighborhood maybe to pedestrians but it has a lot of useful information including some restaurants I was not aware of.