Ring, ring

Except it's never "Ring, ring" these days, it's the theme from Super Mario Bros coupled with vibrate...

What do you as a speaker do when someone's cell phone goes off during a seminar? (The question also applies to other noisy distractions, like hallway noise or a jet overhead, but the cell phone is ever the standard-bearer of unwonted noise.)

For very loud interruptions, I favor the sip of water approach, which makes the speaker look unfazed and vaguely productive. But most of these noises are loud enough to distract but not loud enough to drown out the speaker.

In the early days of cell phones, it was a novelty and the speaker would often make a joke about it. But that diverts attention and gets old fast.

Some speakers will simply pause so as not to compete with the noise. Advantage: the audience's attention is undivided when you resume. Disadvantage: long pause in your talk, and it feels obscurely like the cell phone owner won.

Others will continue talking right over the sound, perhaps at higher volume to compensate. Advantage: no break in your stride, and the speaker sounds unflappable. Disadvantage: audience may not catch what the speaker says or are too distracted to parse it.

I think the best solution, unless the sound is very loud, is to continue talking over the interruption, but then to reiterate the point once the noise has ceased, ideally with a smooth, "In other words..." or "To recap..." or "That is,..."

Less good transitions include, "To repeat without the Lone Ranger soundtrack" or "As you would have heard had it not been for the jerk in the third row..."