http://www.cs.cmu.edu/People/spok/banned-books.html

In a tribute to freedom of thought and speech, “Banned Books Online” offers a representation of texts that have been–or still are–kept from readers by nervous authorities. The site was created by free speech advocate John Ockerbloom and includes a section called “Unfit for Schools and Minors?” which should be of special interest to educators. Ockerbloom notes that Merrimack, N.H., schools pulled Twelfth Night from the curriculum in 1996 as a violation of the district’s ban on alternative lifestyles, for example, and he includes a link to a site that chronicles attacks on Mark Twain, whose Huckleberry Finn remains one of the most censored books in American schools.