Coca-Cola changed its 99-year-old formula in April 1985 and called the new version, predictably, New Coke. The hotline lit up with 1,500 angry calls a day. A protest group - the Old Cola Drinkers of America - signed up 100,000 members. After 79 days of public fury, Coca-Cola brought the original back as Coca-Cola Classic. New Coke quietly vanished.