I learned a few things from Eddie Izzard the other night about how to deal with bombing.
When one of his jokes triggered only a few chuckles, he responded, "Thank you 12 people."
At one point, he said in response to another flat joke, "So it's true but not funny -- that's what you're saying."
Eddie frequently plays two characters having a conversation onstage. During this show, when a joke wasn't working, the two characters would occasionally discuss the audience's response.
All of these techniques brought more laughs.
I think this was my favorite response of the night: "Just shut up, will you? I know one or two people have heckled, but I will kill you. It's the middle of a flow. What was I saying?"
This is a great lesson for speakers. There are times when your audience will start to drift off, not pay attention, or not think your humor is funny.
Instead of panicking and trying to pretend it's not happening, why not address the issue?
You don't necessarily have to be funny when you address it; you could just as easily say, "Okay, let's shake things up for a moment. What would you like to talk about? Who's got some questions?"
But acknowledging a bad joke or some flat humor by saying with a smile, "That wasn't very funny, was it?" can get your audience reconnected with you and show them that you're not just a robot who's going to plow through the material whether it works or not.
By the way, saying "That wasn't very funny, was it?" with a frown or sad look on your face will not have the same effect. You're not apologizing or looking for pity. You're just acknowledging a fact.
At minimum, they'll respond with a relieved "No, that wasn't very funny" (and thank you for noticing). You might even get a laugh!
How have you handled a situation like this?