http://burgerdays.com

For those that aren't famiilar with the Z, it's a Five Guys-style joint, some would say almost a direct copy, offering up very decent burgers of the greasy, fast-food variety. The onion rings are quite tasty, if a little soggy, but skip their fries.

If you're in the area, definitely grab the free burger, but I wouldn't necessarily recommend going out of your way to pick one up.

From WTOP.