"Stop laughing. It's not funny." Those were the solemn words of Jerry Seinfeld during his visit with David Letterman in his effort to rehabilitate the image of his co-star, Michael Richards, aka "Kramer." Richards, as you know, flipped out at an L.A. comedy club and began screaming racial epithets at some black patrons. It was an ugly scene captured on video, and the actor has been apologizing ever since – doing his public penance for a truly shameful exhibition. Watch 'Kramer' grovel on Letterman show The "act" has ignited a national debate on the use of the "N-word." But, having...