"The last question was asked for the first time, half in jest, on May 21, 2061, at a time when humanity first stepped into the light. The question came about as a result of a five dollar bet over highballs, and it happened this way" Two sentences. Oh well.
if you meant power_13's quote it wasn't the opening to slaughterhouse-five. however, slaughterhouse-five was written by vonnegut. in case you were curious the opening line to slaughterhouse-five is: "All this happened, more or less."