National Museum Day

On the same day as the Brookland Festival, there is the National Book Festival, Clarendon Day, the Montgomery County Art Fair--a different name--in Silver Spring and (National) Museum Day:

Museum Day is a nationwide event taking place on Saturday, September 29, 2007, where participating museums and cultural institutions across the country offer free admission to Smithsonian readers and Smithsonian.com visitors. Museum Day celebrates the country’s cultural offerings, allows the dissemination of knowledge and brings Americans together.