Do you know the name of this movie?

i need the name of a movie i cant remember the name of. it's an old black and white movie and on "Gilmore Girls" Rory and Lorelai watched it. they were like, sitting on their couch and the living room watching it in the dark. i need it for a homework reference. please help! and it might have 'cas' in the title. MAYBE. not sure.