I watched a disperse the audience into groups of four people …

And then struggle to get them to stop talking and return their to the stage.

The exercise was a success—the audience got caught up in their conversations—but how do you break up the party so you can continue with your presentation?

Train your audience—before you ask them to engage in group activities.

In a moment, I'll ask you to make a lot of noise.
Then I'll blow my whistle twice.
The first you hear it, you'll know you have five seconds before the second whistle cues you to go completely silent.
Even if you're halfway through a sentence, just stop. We'll all understand.
Ready? Make lots of noise.
(First whistle)
(Second whistle)
Great. Let's try that one more .

Train your audience to stop talking on command. They'll enjoy the game, and when it's your turn to speak again, they'll be focused and ready.