Nobody did a double-take, much less a triple-double-take, upon hearing that Magic Johnson's late-night car wreck of a talk show, The Magic Hour, had been canceled last week. After all, when you resort to staging a contest that gives an audience member the chance to win a date with your sexy bandleader (Sheila E.), a ploy that we would love to see David Letterman mimic, you're just a step up from a tag-team wrestling match. Oops, sorry, Jay. Magic's final act on his farewell show last Thursday was fitting: He took an errant shot at a hoop with a red-white-and-blue ABA basketball. In other words, it was a game effort, Earvin, but you were out of your league.