1) Washington National Airport has a new cell phone parking lot. When picking people up, you can now sit with your car in the free lot to wait for them to call you to say they've arrived. This is, of course, better than the alternative, which had been to drive laps around the airport until you ran out of gas and had to push your car home. (Well, the actual alternative was to pay for real parking, I suppose.)
BWI has had a cell phone parking lot for awhile, but I've never used it because they also have a "smart parking lot" that is free for one hour. (BWI's "smart parking lot" probably deserves its own post sometime, since it's the single greatest thing I've ever seen in the history of my life.)
2) A company called D.C. Pedicab has unveiled a bicycle cab service. A ride on the bike rickshaw costs about $5. As strange as they are, Pedicabs might be pretty useful to get around on the National Mall to places like the FDR Memorial. And evidently they pay "drivers" $20 per hour.