I personally love failed predictions. Some of the best I've heard are:
"That rainbow song's no good. Take it out." MGM memo after first showing of "The Wizard Of Oz."
"Everything that can be invented has been invented." - Charles H. Duell, Commissioner, US Office of Patents, 1899.
"Stocks have reached a permanently high plateau." - Irving Fisher, Professor of Economics, Yale University, 1929
"Where a calculator on the ENIAC is equipped with 19,000 vacuum tubes and weighs 30 tons, computers in the future may have only 1,000 vacuum tubes and perhaps only weigh 1.5 tons." - Popular Mechanics, forecasting the relentless march of science, 1949.
"I think there's a world market for about five computers." - Thomas J. Watson, chairman of the board of IBM.
"But what [...] is it good for?" - Engineer at the Advanced Computing Systems Division of IBM, 1968, commenting on the microchip
"There is no reason anyone would want a computer in their home." - Ken Olson, president of Digital Equipment Corp. 1977
"Drill for oil? You mean drill into the ground to try and find oil? You're crazy." - Drillers who Edwin L. Drake tried to enlist in 1859.
"$640K ought to be enough for anybody." - Bill Gates, 1981.
"Men might as well project a voyage to the Moon as attempt to employ steam navigation against the stormy North Atlantic Ocean." - Dr. Dionysus Lardner, Professor of Natural Philosophy and Astronomy, University College, London, 1838