"He likes it! Hey, Mikey!" Who doesn't remember and love little chubby-cheeked Mikey, played by then-3-year-old John Gilchrist? The ad has been a mixed blessing for Life owner Quaker Oats; they've been trying to come up with a fresh campaign ever since, but focus groups tell them that Mikey's is the only one they like. In '86, Quaker gave up and shot an updated version with an 18-year-old Gilchrist; the results were pretty Life-less