One of my favourite jokes for pedants.

What’s blue, hangs on the wall, and whistles?

Pedant: I don’t know, what’s blue, hangs on the wall, and whistles?

A herring.

Pedant: But a herring isn’t blue.

So you paint blue.

Pedant: But a herring doesn’t hang on the wall!

So you nail it to the wall.

Pedant: BUT A HERRING DOESN’T WHISTLE!!!

So a herring doesn’t whistle. It’s a joke!