Oklahoma City punches above its weight for a Plains city. The unmissable sights are the Oklahoma City National Memorial (allow at least two hours, ideally with the museum) and the National Cowboy & Western Heritage Museum — easily the best Western museum in the country. Add the spectacular new First Americans Museum, devoted to the thirty-nine tribes headquartered in Oklahoma, and a contender for one of the most important new American museums of the last decade.
For an evening, head to Bricktown for the canal, the Land Run Monument, and a brewpub dinner; or to the Plaza District for something less obvious. The Stockyards livestock auction (Monday and Tuesday mornings) is a genuine piece of American West history still in operation, and Cattlemen's Steakhouse next door is the city's signature meal.
For something different, the city has a remarkable density of small specialist museums — banjos, pigeons, women pilots, osteology, firefighting, Western art — most of which are free or cheap and worth a side visit if the topic catches you.