Amused Grunt?

You know that sound people make when something is intended to be funny, but isn't funny, but those same people want to acknowledge the fact that they understand that it is intended to be funny (but in fact, is not funny)?

Is there a word for that? 'Amused Grunt' kind of captures it, but leaves out the fact that the failed intended funnyism...isn't.

Pseudo Amused Grunt?
False Chuckle?
Pho Chuckle?

Help me out here.

Anyway - once we define the term, I have a contribution:

"As wrong as a bee drunk on mead!"

Yep, I'm so darn funny that I just made that up. It has the added benefit of being suitable for use in historical works.