Just for posterity, this is totally my favorite movie. I don't even know how many times I've watched it staring in high school, and, somehow, I still think it's funny.
Way back in like 2008 or so I went through the interview process of a new job. The last step was a panel interview with the people who would report to me. Their last question was, "what is your favorite movie." When I told them "The Holy Grail" it absolutely sealed the deal for them. It turned out to be a great team and a great fit, too.
I'm glad that story turned out well, but I've really come to detest that kind of cultural thing being part of a hiring process.
I once interviewed for a job, probably 12 interviews with different people over two weeks, everything was going spectacularly, and then the final interviewer just didn't like me culturally for whatever reason, and made that clear in the interview. (And he wasn't even someone I'd work with if I were hired.) But their hiring process required unanimous approval. So I didn't get the job. (An acquaintance of mine on the team confirmed that was why.)
Having to answer a question about your favorite movie isn't right, even if it seems like it's just "fun". You hope it's not something that would ever swing the interview in your direction, but it's certainly something that can lead them to dislike you for reasons entirely unrelated to the job. ("Ugh, Fellini/Bollywood/Midnight Cowboy? What a weirdo. They seemed cool till now. Never mind, pass.")
... but if they do ask the question and then despise you for your answer, isn't it best to surface that during the interview rather than after you've made a commitment to spend 8 hours a day with those people?
Way back in like 2008 or so I went through the interview process of a new job. The last step was a panel interview with the people who would report to me. Their last question was, "what is your favorite movie." When I told them "The Holy Grail" it absolutely sealed the deal for them. It turned out to be a great team and a great fit, too.