Five Guys Burgers, located all over DC and northern VA.  This local chain features handmade fresh beef patties, and fresh cut homemade skin-on french fries.  In fact they will tell you where in Idaho today's potatos came from.  Not fancy at all.  Food served in a paper bag, but it's where the locals get a great lunch.  Voted DC's Best Burger many years in a row by local magazines.

 Five Guys is great, but it is just food court stuff.  If you want an awesome burger go to Mr. Smith's in Georgetown.  When you are tired of touring about on a hot summer's day bring the kids to the back garden at Mr. Smith's - give them burgers and enjoy cool daquiris.  It is a gem.