National Book Festival kicks off Saturday Book lover alert! 2011 National Book Festival. (Megan Buerger - THE WASHINGTON POST) The 12th annual National Book Festival kicks off on the Mall this weekend with a full program of author readings, signing sessions and a salute to Clifford the Big Red Dog, who turns 50 - yes - 50 this year. This is one of those signature events that book loves wait for all year. In fact, the festival hosted by the Library of Congress, has proved so popular, this is the second year it will run for two days. With the weather expected to be sunny and not too hot, it will be a great day to be out. Note: There is a possibility of rain in the afternoon - so keep that in mind. Be sure to check out Book World's special section, which includes a handy map, schedule as well as author interviews. Want to follow the festivities via Twitter? Follow The Post's own Ron Charles - Book World's deputy editor @RonCharles - as well as staff writer Megan Buerger @MeganBuerger and myself @loriara. Want to send along your photos or observations? Ship "em to @postlocal and be sure to tag your tweets with the official #NatBookFest hashtag. Follow our tweets here: