Is this funny? My sister thinks it is and I dont?

My sister said a friend asked her if she had watched the batman vs wolverine movie. When she realised that her friend was refering to the movie 'The Prestige' starring Hugh Jackman of X-Men and Christian Bale of Batman Returns, she laughed her head off. I didn't think it was funny at all but she thinks my sense of humour needs some checking. What do you guys think? I am also wondering if guys and girls interprate 'jokes' differently.