“It’s All in the Cards”: card catalog card shenanigans.
Year-long celebration at the University of South Carolina, 2009. http://www.sc.edu/library/inthecards.html Includes a slideshow of actual cards and contests involving cards. (Thanks, BoingBoing!)

Mickey Smith’s gorgeous photographs of bound journals in libraries. Various libraries, credited here, ca. 2009. http://www.mickeysmith.com/installations.htm (Thanks, Steve Lawson!)

Guild of Radical Militant Librarians t-shirt and totebag. Guild of Radical Militant Librarians, which doesn’t exist. http://www.instantattitudes.com/shirts/t052.html (Thanks, Matt Grant!)

Librarians all over the world are members of this society created in April 2007. Founder, Sheriff, and Co-Carping Nerdboy: Joshua M. Neff. Other Co-Carping Nerdboy: Steve Lawson. http://thelsw.org/ Home of a zine (Codslap! aka Librarian Bomb), the Shovers and Makers award, and plenty of other shenanigans.
To quote the site: “Just kidding. Sort of.”

Photograph by Peruvian artist Diego Lama. Library in Lima, Peru, 2007. http://www.peakradar.com/event/detail/38385 (Thanks, The Big Something!)

Student-made mockumentary, Penrose Library, Whitman College, 2008. http://forkeepingtime.blogspot.com/2008/10/library-as-placearound-1-am.html (Thanks, Michael Paulus!)

Greene: Don’t Let the Bedbugs Bite (Denver Post article). Denver Public Library, September 22, 2009. http://www.denverpost.com/news/frontpage/ci_13390297 This one is not a lighthearted shenanigan but a sad story. (Thanks, Steve Lawson!)

Addendum, August 2012: bedbugs shut down a library in Middletown, CT. Thanks, David Weinstock!

Library promo in the style of an old-timey silent film. Collingswood Library, Collingswood, New Jersey, July 2009. http://www.youtube.com/watch?v=11Wx25Mk-Ek (Thanks, Joan Petit!)

Awful Library Books blog, with examples of books from public libraries all over the U.S. Mary Kelly and Holly Hibner, public librarians in Michigan. awfullibrarybooks.wordpress.com/ (Thanks, BoingBoing!)

Aaron Andzick’s commercial for the re-opening of the Fairfield County Library, Fairfield, MA, 2009. http://www.funnyordie.com/videos/a121f641d8/library-reopening-aaron-andzik-from-aaron-andzik When’s the last time you were at the library-ibrary-ibrary-ibrary?