Serious Eats - seriouseats.com

Not far from Georgetown, I highly recommend Chef Geoff's. While I'm not a fan of their food generally, it's hard to beat their $5 burger and fries happy hour special (all day on weekends). The burgers use great meat and are properly cooked to temp (toppings like bacon and cheddar included for $5). The fries are thin and crisp. Paired with an $8 supermug of a great microbrew, it makes for a tasty and filling dinner. Great after work or, for tourists, after a day of sightseeing.

Now that my husband and I have left D.C., we compare all burgers to Chef Geoff's.

http://www.chefgeoff.com/main/index.cfm?Restaurant=cg_downtown&Category=Events&Section=Main