My last visit to DC was 20 years ago when I first moved to the US at the age of four, an age far too young to appreciate what a fun city it is.
Of course, now that I actually care about money, the first thing that struck me about DC is the plethora of free activities; I especially enjoyed the Smithsonian, a museum so expansive and fascinating that I would have gladly paid for it. I highly recommend DC to anyone looking for a quick get away; flying into Baltimore (an hour away, where I lived for a year and a half in my childhood and is a city definitely NOT worth visiting) from Chicago was just $87 round trip!
But onto the food! By far the most important part of any trip across the country (other than friends, of course).