Remember Donald Rumsfelds discourse on “known knowns, known unknowns” and everything in between? Well Washington, D.C., (better known as simply “D.C.” or “the District” to locals) is about to experience a major known unknown next week when untold masses descend upon the capital for perhaps the biggest Presidential inauguration in our lifetime. D.C. officials have ratcheted down their initial doomsday estimates of four million to maybe half that, but it’s still going to be interesting, to say the least.

If you happen to be among the millions without tickets to any of the official events, take heart. First of all, the exceedingly crowded inaugural “balls” apparently aren’t at all like the elegant Gilded Age affairs you might imagine. Second, D.C. is a great place for art viewing, whether in the Greek revival grandeur of the big museums or in smaller galleries off the beaten path. You might want to vet your sightseeing candidates ahead of time, though, since change, including last-minute adjustments of hours, might very well be in the air.

The recently renovated National Portrait Gallery has become a must-see on the major museum circuit. As with all Smithsonian houses, admission is free, and Presidential portraits abound, including the recently unveiled portraits of W and Laura, if you’re into that sort of thing. There’s a special exhibition on “The Mask of Lincoln” running through July 5 that is sure to inspire, what with all the talk these days of teams of rivals. And if you see nothing else, walk through the elegant new courtyard, capped by a signature (and, at one time, much-debated) Norman Foster ceiling of glass and steel. You can also follow the Mona Lisalike crowds to the original Shepard Fairey “Hope” portrait of the President-elect, recently acquired by the museum.

Other big-ticket museums are also getting into the inaugural spirit. The National Gallery of Art pays tribute to amber waves of grain and purple mountain’s majesty (in tasteful black-and-white, mind you) in a show of landscape photography by Ansel Adams, Robert Adams, and Alfred Stieglitz, through March 15 (also free admission, but closed on Inauguration Day proper for security reasons). And the recession-conscious can also take advantage of a two-for-one admission offer at Dupont Circle’s charming Phillips Collection, which has an exhibition about Christo and Jeanne-Claudes latest project on view through January 25. Within spitting distance of the White House, the Corcoran Gallery of Art is offering two-for-one tickets as well, for its special show “Richard Avedon: Portraits of Power,” including one of the President-elect himself, on view through January 25, the last day before the museum closes for six weeks of renovations. (Go on the Web site for a coupon.)

Although the big museums consistently draw the tourist millions, aficionados would be well-served to sample the thriving local art scene in smaller galleries throughout the city. A visit to the newly revived corridor along 14th Street NW, just north of downtown from Thomas Circle up to U Street, is the place to escape the hordes near the Mall. The boarded up storefronts left over from the ’68 riots have given way over the past 10 years to a thriving retail and entertainment district. Whether you’re discovering the stunning molten-glass-on-paper creations by Seattle’s Etsuko Ichikawa at Randall Scott Gallery, opening January 17, or checking out the range of works on paper at Transformer gallery just off 14th on P Street, you’re sure to find something new and inspiring. And at 1515 14th Street, three notable galleries have set up shop in a large arts and theater complex (G Fine Art, Adamson Gallery, and Hemphill Fine Arts) for convenient one-stop gallery hopping.

And if you are still set on attending a ball, stop trying to call in favors from your well-connected friends and give something different a try. “The Art of Change: An Inaugural Celebration of D.C.’s Creative Communities” on January 20 will feature DJs, musicians, theater performers, poets, dancers, comedians, and visual artists from D.C. and all over the East Coast. Held at the hip Warehouse Complex on 7th Street NW — across from the hulking Convention Center where a half dozen of the official balls will be taking place — the event will include three dance floors, a variety stage, the Art of Change gallery, and much more all night long. For info on how to get tickets and how to participate as an artist or performer, go to www.artists-ball.org.

Wherever you end up on Inauguration evening, make sure you are near a friend with an iPhone so you can get a real-time answer to the question that will be on everyone’s mind. Thankfully it will not be about the latest gyrations of the stock market but rather “The Dress” — you know, the one that she will be wearing. Because whatever Mrs. O picks, you know it’s going to be fashion we can believe in.