When film critic Roger Ebert heard that editors were censoring out the N-word from a new version of "Huckleberry Finn" and "Tom Sawyer" he sounded off on Twitter. That sounding off included using the N-Word. When he realized that might not have been the best choice, he decided to apologize...using the N-word.
Ebert faced fierce criticism for that message, and one person pointed because he's white would probably never be called either. So, in one of the smartest moves in the history of tweeting, he apologized for it by using the word again:
Part of thinks that "apology" is slightly sarcastic.