DC residents know tourists suck: they're annoying, they stand on the left side of the escalator, and they think "the speaker of the house" is what you hear pumping out the beats at Lima. See the world while sparing its peoples your plague, with Tour Wrist.
A free iPad/iPhone app that acts as a e-viewing portal for destinations all over the planet, TW actively tracks the movement of the device in the user's hands as it turns and tilts to dynamically display any angle they go for, unless they're going for the "not looking weird swinging around their iPad on the sidewalk". The current view-cache's at 3,000 (though they plan to be up around 165,000 by the end of the year....) with spots ranging from well known tourist sites, to hotels, restaurants, and random real estate, all of which've been captured in complete 360-degree splendor by photogs using panoramic camera heads called "Nodal Ninjas", which take better photos than knockoff "No-Dough Ninjas". Though the site's soon to be bolstered by allowing all-comers to load their own "AmaTour" videos, current/awesome offerings include domesticity like the sunny Chicago River and neon-lit Vegas Strip (strangely from the passenger seat of a convertible with some random dude...), to international sites like the Thai Buddhist temple Wat Chaiwatthanara (awesomely next to some random Thai woman...) to a beautiful sunset in Harissa, Lebanon, to a busting rural market they title "China Daily" -- also the name of a newspaper that reports only good news, all the time, because nothing bad happens there, ever.
They'll also soon be rolling out advanced search features, and a heat-mapping function to highlight the spots lots of users are checking out, which during Inauguration/Cherry Blossom Festival/4th of July, will definitely be on K Street.