HARRY: Back at Griffindor at last!
THE FAT LADY: Hello, Harry. Hello, Ron. Glad to see you back
HARRY: We're glad to be back. Can we come in, please?
THE FAT LADY: Fat chance without the password, dear
HARRY: But we don't the password!
RON: Maybe trying random phrases will work. Pudding fork? Butter polish? Fish whistle?
HERMIONE: Maybe you should try "traffic violation" instead.

   Harry Potter and the Chamber of Secrets