The local museums will also be rolling out:

Oct. 16: How clean is clean enough? That is just one question that will be explored in "History in a Vacuum (The Real Dirt)," a complete look at housecleaning and the development of the electric vacuum cleaner. The National Museum of American History will display several vacuums from the first invented in 1910 and trace changing attitudes toward housework through advertising images, comic books and cleaning tools.

Nov. 18: Why American society is driven by time will be the focus of a sprawling exhibition at the National Museum of American History. "On Time," a permanent exhibition, will showcase 200 clocks and the skeleton of "Lexington," a famous 19th-century racehorse because, the curators tell us, fractions of seconds count in horse racing and a stopwatch is essential.

Nov. 19: The elephant that has graced the Rotunda of the National Museum of Natural History for decades is getting a new habitat. It will move slightly off-center and will stand on a platform that will describe the grasses, insects, birds and other animals that live around the elephant. Visitors will be able to use a computerized viewer from the second-floor balcony and identify "hot spots," such as elephant dung and stripped tree trunks, in the environment and then see a special film about the subject.