Banned Books Week: Celebrating the Freedom to Read is observed during the last week of September each year. Observed since 1982, this annual ALA event reminds Americans not to take this precious democratic freedom for granted. This year, 2006, marks BBW's 25th anniversary (September 23-30).
BBW celebrates the freedom to choose or the freedom to express one’s opinion even if that opinion might be considered unorthodox or unpopular and stresses the importance of ensuring the availability of those unorthodox or unpopular viewpoints to all who wish to read them. After all, intellectual freedom can exist only where these two essential conditions are met.
American Library Association website
Google on banned books
Wikipedia entry on banned books