When keynote to over 200 people yesterday, I told them we would do an activity that involved my reading a passage to them. I gave them instructions on what to do, and when I looked for the passage, I didn't have it on me. There they were waiting for me to start reading.
I said "Hold on" and I walked off stage to my bag and searched for the piece of paper, while the stage was empty and people didn't know what to do. Luckily I found it, came back, and reflected on my mistake as a teachable moment.
Later I learned from my pro wife that in that situation I could have asked them to talk to their neighbor, which would have been a lot smoother.
Lesson learned: bring with me on stage the passage I want to read to them...