Ah, the nipple scene. In the realm of unexpected Mad Men moments, this one takes the cake (next to the lawnmower incident). When the new computer moves in, Ginsberg starts to feel threatened; first, it's his creativity, then it's his manhood. He gets it back by cutting off his nipple and presenting it to Peggy. Look, Ginsberg has always been a strange dude, but it's sad to see his mental state degrade like this.