Bananas

[Rondy]

Two guys go into a pub. There is a swing band playing the old song "Yes, we have no bananas".

Guy 1: I love this song!

Guy 2: Yes. I think it's written by Mozart.

Guy 1: Of course it's not. They didn't make swing music in Mozart's time.

Guy 2: Yes they did!

Guy 1: You're stupid! They didn't even have bananas back then.

Guy 2: I know, that's the name of the song!

[fourteen85]

Is there anything missing? (Apart from Bananas), a punch line maybe