8½ (1963) was shot, like almost all Italian movies at the time, completely without sound recording on set. All dialogue was dubbed during post production. Federico Fellini was known for shouting direction at his actors during shooting, and for rewriting dialogue afterwards, making a lot of the dialogue in the movie appear out-of-sync. (Source: High-def Digest)
Federico Fellini attached a note to himself below the camera's eyepiece which read, "Remember, this is a comedy."
Often cited by Federico Fellini himself as one of his favorite films ever, even considering other directors' works.
The title refers to the number of movies Federico Fellini had directed up until that point - six features, two shorts (films #7 and #8) and a co-directed film with Alberto Lattuada, for a total of 8 1/2 films.
Federico Fellini was well-known for working without a stable, finished screenplay. At one point during pre-production, he had completely forgotten what his next work would have been about; his original idea had completely gone. While he was set to communicate to the movie producer Angelo Rizzoli his intention of abandoning the project, Fellini was invited to the birthday party of a head camera operator of Cinecittà. All of a sudden, during the celebration, he got a new idea: his film would have told about a film director who was going to direct a film, but he forgot what it was about. Fellini said that he hoped to convey the three levels "on which our minds live: the past, the present, and the conditional - the realm of fantasy."