Here are some exhibits related to Time and Frequency...
An illustrated history of timekeeping from ancient to modern methods.
A short overview of our current calendar, as well as other ethnic and historical calendars. (At webexhibits.org)
Discover the fascinating stories behind the invention of the quartz watch. (At the Smithsonian Lemelson Center)
Daylight saving time, its history and why we use it. (At webexhibits.org)