Banned Books Week
Banned Books Week is the national book community’s annual celebration of the freedom to read. Hundreds of libraries and bookstores around the country draw attention to the problem of censorship by mounting displays of challenged books and hosting a variety of events. Banned Books Week is held annually on the second to last week of September.
University of Pennsylvania Banned Books Page
And older page on banned books, but with lots of good info on the history of banning books.