Museum Day is an annual event hosted by Smithsonian Media in which participating museums across the country open their doors for free to anyone presenting a Museum Day Ticket.
 
Offer is valid only on Saturday, September 25, 2010.  The Museum Day Ticket provides free admission to one person, plus a guest. 
 
Signup and print your ticket here:
 
  http://microsite.smithsonianmag.com/museumday/