This special rate is called their "Web Special". They make it available for weekends where they're not selling out. And sometimes it's not even advertised on their corporate website, so be sure to call the directly.
As you can see on the map, it's only about 10 blocks northwest of the White House and only 4 blocks from colourful Dupont Circle.
The closest metro stop is "Foggy Bottom - GWU", down New Hampshire Avenue, just on the other side of Washington Circle.







