That's the sound of crickets, see.

A good way to insult someone without him knowing it, would be to talk him up for 6 months, or so, and make him think he's a pretty funny guy. You laugh at all of his jokes, but really, all along, you are plotting. Then what you do is get him a gig at a stand up place, and pay the entire audience not to laugh at anything he says. You will want to make sure that you are a person who has a lot of money; If you're not, this plan may not work for you. During his show, he'll probably be thinking he would rather take a dirt nap than face these people, and you'll be up in the opera box enjoying your Jujyfruits.