In 2006, there were a total of 63 challenges to books, materials, events, and exhibits in Colorado public libraries. This was the lowest number of challenges since 2003. Of the 115 public libraries in the state, 23 had a challenge during the year. And Tango Makes Three by Justin Richardson was the title most often named in a challenge.
Source: http://www.lrs.org/pub_stats.php

The first Index of Prohibited Books was drawn up by order of Pope Paul IV in 1559. The lists were issued 20 times through the centuries by different popes, the last issued as recently as 1948, and finally suppressed in 1966.
Source: http://www.beaconforfreedom.org/about_project/history.html

The origin of the term censor in English can be traced to the office of censor established in Rome in 443 BC. In Rome, as in the ancient Greek communities, the ideal of good governance included shaping the character of the people. Hence, censorship would have been regarded as an honorable task.
Sources: http://www.beaconforfreedom.org/about_project/history.html and http://encyclopedia.farlex.com/censor+(magistrate)

The first recorded book burning in the United States was in 1650. William Pynchon’s A Meritorious Price of Our Redemption was ordered destroyed by a court because the religious publication contained “errors and heresies.” The book was burned by the public executioner.
Source: http://www.firstamendmentcenter.org/commentary.aspx?id=2264

Aristophanes’ Lysistrata, Chaucer’s Canterbury Tales, Boccaccio’s Decameron, Defoe’s Moll Flanders, and various editions of The Arabian Nights were all banned for decades from the U.S. mail under the Comstock Law of 1873. Officially known as the Federal Anti-Obscenity Act, this law banned the mailing of “lewd”, “indecent”, “filthy”, or “obscene” materials. The Comstock laws, while now unenforced, remain for the most part on the books today; the Telecommunications Reform Bill of 1996 even specifically applied some of them to computer networks.
Source: http://onlinebooks.library.upenn.edu/banned-books.html

50 years ago Poet Lawrence Ferlinghetti contacted the ACLU to defend the publication of Howl. U.S. Customs officials had seized the books, stating, “You wouldn’t want your children to come across it.” A state court judge ruled that the poem could not be suppressed as obscene by local authorities.

In 2007, fearing repercussions from the FCC, in a New York radio station decided against airing Howl on the 50th anniversary, choosing to stream the poem on its web site instead.
Sources: http://www.nytimes.com/2007/10/04/books/04howl.html?_r=1&oref=slogin
http://www.aclu-wa.org/library_files/A%20History%20of%20Fighting%20Censorship.pdf

The ALA Office of Intellectual Freedom reports there were more than 3,000 attempts to remove books from schools and public libraries between 2000 and 2005. J.K. Rowling’s Harry Potter series tops the list of the most challenged books of the 21st century. Source: http://www.ala.org/ala/oif/bannedbooksweek/bbwlinks/topten2000to2005.htm

The Lorax by: Dr. Seuss was banned in the Laytonville, California School District on grounds that this book “criminalizes the forestry industry.”
Source: http://library.dixie.edu/new/whybanned.html

To Kill a Mockingbird by Harper Lee was banned as recently as August 2001, in Oklahoma for “racially charged language.” It was also banned from the Lindale, Tex. advanced placement English reading list (1996) because the book “conflicted with the values of the community.” Also challenged at the Warren, Ind. Township schools (1981), because the book “represents institutionalized racism under the guise of ‘good literature’.” Also challenged–and temporarily banned–in Eden Valley, Minn. (1977).
Sources: http://library.dixie.edu/new/whybanned.html http://title.forbiddenlibrary.com/

The Intellectual Freedom Committee of the Colorado Association of Libraries has information on how libraries can deal with challenges and other important information:
http://www.cal-webs.org/ifhandbook.html
For more information about banned books visit:

Banned Book timeline
http://www.thebookstandard.com/bookstandard/news/global/article_display.jsp?vnu_content_id=1001181785
American Library Association
http://www.ala.org/ala/oif/bannedbooksweek/bannedbooksweek.htm
And finally a few quotes to end our Who Knew about Banned Books:

“Books and ideas are the most effective weapons against intolerance and ignorance.”
— Lyndon Baines Johnson, February 11, 1964

“Quis custodiet ipsos custodes? – Who will watch the watchers?”
— Juvenal