The problem with bank call centers are that they can't see your ID to prove you are who you say you are. One good way to get around that is to have the person make up questions themselves since finding out your mother's maiden name is way too easy. Its much more secure and as you can see below, allows you to be creative. I didn't come up with these but I think they're pretty funny.
Teller: Do you know why I think you're so sexy?
Customer: Probably because you're totally in love with me.
Teller: Need any weed? Grass? Kind bud? Shrooms?
Customer: No thanks hippie, I'd just like to do some banking.
Teller: The Penis shoots Seeds, and makes new Life to poison the Earth with a plague of men.
Customer: Go forth, and kill. Zardoz has spoken.
Teller: What the heck is your problem, sir?
Customer: This is completely inappropriate and I'd like to speak to your supervisor.
Teller: I've been embezzling hundreds of thousands of dollars from my employer, and I don't care who knows it.
Customer: It's a good thing they're recording this call, because I'm going to have to report you.
Teller: Are you really who you say you are?
Customer: No, I am a Russian identity thief.