I think the most effective way to get people to stop using the "r word" is not so much to try to ban its use or impose some kind of embargo on it. That approach just seems to bring out the worst kinds of entitled, obtuse, "Fight the Man" arguments about what the word technically means and how we should just make the choice not to be offended, etc. Trust me, I know.
I like this PSA because it makes what I believe is a more effective point, that you ought to care how much your words hurt someone else, but even if you don't, calling someone a retard simply makes you look like a bigot. Or rather, it alerts the world that you ARE in fact a bigot.
Thanks to the Spread the Word to End the Word campaign (sponsored by Special Olympics and Best Buddies), and particularly to Lauren Potter and Jane Lynch. I like this PSA very much.
(I'm still not going to watch Glee, though. Sorry.)