Here are some of my favorites:
Two of the movies I watched from 1929 (Applause and Broadway Melody) involved young women trying to make a living in show business in New York. In both movies, they make a reference to going out for some chop suey. This stuck out to me because although I've heard of the dish, I don't think I've ever tasted it. I've eaten Chinese food plenty of times, but I can't recall if chop suey was ever even on the menu.
This one is my favorite. It looks like the cover of an Ayn Rand novel.