Today is the 12th Annual Space Day, an event that's jointly hosted by NASA and Lockheed Martin, held each year on the first of May. This year's theme is titled : 'Celebrating Human Space Flight: Past, Present and Future'.
Despite the event's name, the activities will actually continue through May 2nd, where there will be a celebration at the Smithsonian's National Air and Space Museum in Washington, DC. Astronauts from the recent Shuttle mission, STS-119, will be present, and there will be a live broadcast from the International Space Station.
The overall focus of this event is education, and as such, schools and civic groups have been invited and encouraged to participate. According to NASA, there will be educational activities at the museum from 10 a.m. until 3 p.m. EDT.
More information can be found here : http://www.spaceday.org
Image from the South Dakota Space Grant Consorteum, 2002