The Jazz Singer (1927)

Continuity mistake: Jack is finished singing Toot-Toot Tootsie and the audience is applauding. The guy sitting to the viewers left, with no cut-aways suddenly has a cigar appear in his mouth, he removes it then its back in his mouth.

Jack Robin: We in the show business have our religion too - on every day, the show must go on.

Trivia: This was the first movie ever with audible dialogue, though less than 400 words are spoken in the whole movie.