Oh, dear! Do Christians have those jokes too?

What's green, hangs on the wall, and whistles?
I don't know.
A herring.
But a herring isn't green.
It is if I paint it green.
But it doesn't hang on the wall.
It does if I hang it there.
But how can a herring whistle?
Nu, so it doesn't whistle.
    or
So I lied.
    or
I just put that in to make it harder.