The week’s must-see event is Friday’s farewell to Johnny (see cover story, page 75). No announced guests, but a studio full of invited friends and who-knows-what surprises. In an unprecedented display of respect (Or is it just bowing to the inevitable?), a couple of Carson’s competitors are funneling their viewers to his final show. Arsenio is scheduling a rerun, saying he’ll be home watching Johnny, and he thinks everyone else should be too. And cable’s Comedy Central will show a graphic recommending viewers switch over to NBC. If Comedy Central’s ratings go up Friday, when the channel is essentially showing a blank screen, it may be time to reconsider its programming philosophy.