How is it that Aug. 21 has not yet been declared Dirty Dancing day? On this date 35 years ago, the little rom-com-musical directed by Emile Ardolino hit theaters and soon became a global sensation.

Thirty-five years later, we're still having the time of our lives. Made for just $6 million, no one expected Dirty Dancing to be a hit—let alone become an enduring pop culture phenomenon—when it was ...