The delightfully light Midnight In Paris turned out to be Woody Allen's highest grossing film ever, as well as one of his best-reviewed films ever. As it turns out, the winner for this year's Oscar for best original screenplay came from an idea from almost 50 years ago—the bits about the Lost Generation were first used in his standup routine in the mid-'60s, as you can hear below. It seems people in the '60s thought Gertrude Stein jokes were utterly hilarious.
The Lost Generation bit mentions all the major "characters" who would populate the fantastical sequences in the film, including Stein, F. Scott and Zelda Fitzgerald, Ernest Hemingway, and Salvador Dali—the "good novel, not a great one" Stein line was actually in the film. Nerdist, who wrote about the clip, wonders if Allen felt the need to resuscitate this bit after all these years: "I imagine that Woody Allen loved that bit so much, especially since he closed some shows with it, that he didn’t want to let it fall into the obscurity of a stand-up compilation album. I imagine that he had sort of a blind faith in how funny it was to the point that it rested in the recesses of his mind until he determined that the idea to make a movie with unexplained time travel is what the joke really needed. "
This wouldn't be the first time Allen has re-purposed old material, or revived a half-finished work: the screenplay for Manhattan Murder Mystery started out as Annie Hall, but was shelved for over 20 years for being too lightweight. The script for Whatever Works was written in the early '70s, with Zero Mostel in mind for the main character; it was shelved for over thirty years after the actor's death in 1977. And Hollywood Ending has possibly the best story, according to IMDB: Allen wrote the concept for the film on the back of a matchbook, discovered it years later, and made the film.