Banned Book Week is an annual event celebrating the freedom to read. It is held during the last week of September and it highlights the value of free and open access to information.
Banned Books Week was launched in 1982 in response to a sudden surge in the number of challenges to books in schools, bookstores and libraries. According to the American Library Association since 1982 more then 11.300 books have been challenged.
For more info visit: http://www.bannedbooksweek.org.
Browse websites to have a look to the list of books banned in your country, and why they have been banned. Here some example from the American Library Association.