Design for Living (1933)
"... but it isn't fun enough to take the place of one hundred percent virtue and three square meals a day."
Design for Living is what happens when you add Ben Hecht to Noel Coward, deliver through Edward Everett Horton, and let Ernst Lubitsch surround you with eye candy like young Gary Cooper and Frederic March. It's the story of Gilda Farrell (Miriam Hopkins), a commercial artist, who meets a struggling playwright (March) and painter (Cooper) on the train to Paris, falls in love with both, but can't decide between them.
It's a smart, funny, modern (by that I mean they use the word "sex"), and sophisticated (by that I mean they don't use the word "f**k") story that may surprise you. Frederic March is very funny, for instance, Gary Cooper speaks French, for another, and Miriam Hopkins holds her own (I'm not her biggest fan) in this believable, never-resolved love triangle.
The best news is that you can watch it in pieces on YouTube or see the whole thing on DVD all at once without remembering which part you're on.