Dec. 4, 1956.In a rock 'n' roll moment so surreal you'd swear it was scripted for a movie, music superstars Elvis Presley, Jerry Lee Lewis, Carl Perkins and Johnny Cash came together in the afternoon for an impromptu jam session at Sun Record Studios in Memphis.It was a moment that should never have happened. Presley, who had recorded for Sun Records, was now an RCA artist. Johnny Cash had just stopped by to listen to Carl Perkins' recording session (or pick up a check, depending on what version of the legend you believe). Jerry Lee Lewis was a relatively unknown performer outside of Memphis and was there just to provide some piano pizzaaz on Perkins' recording.It was a one-in-a-million chance that these four rock 'n' roll superstars would meet and become, for a few hours, the Million Dollar Quartet.More than 50 years later, the moment has been been musically brought to life in the hit Broadway show "Million Dollar Quartet" now playing at Harrahs Las Vegas.We know exactly what was sung on that fateful December day at Sun Records because Jack Clement, the engineer for Perkins' session, recorded it. The session mainly featured gospel songs, but also a number of country and western songs by Bill Monroe, Ernest Tubb, Hank Snow and Gene Autry. Elvis' recent (at the time) hits "Don't Be Cruel" and "Love Me Tender," as well as Lewis' song "End of the Road.""Million Dollar Quartet" the show takes a little more license, using that famous recording session as a springboard to imagine what it would sound like if Presley, Cash, Perkins and Lewis had the benefit of time to sing their greatest hits.Featured songs in the show include "Blue Suede Shoes," "Real Wild Child," "Who DO You Love?," "Folsom Prison Blues," "I Walk the Line," "Hound Dog, "Great Balls of Fire," "Whole Lotta Shakin' Goin' On," "See You Later, Alligator," "Riders in the Sky," and more.The show gives a nod to the original session with performances of "Peace In The Valley," "Brown Eyed Handsome Man," and "Down By The Riverside."It was 25 years before the recordings of that December day were rediscovered and released. And another six years after that before the complete jam session was made available to the public."Million Dollar Quartet" ensures that Dec. 4, 1956, will be a day you'll never forget.