Rock-paper-scissors

"Rock-paper-scissors, OK?" "Rock." "Sciss... paper." "You cheated!"

Let's have the one who loses at rock-paper-scissors do the dishwashing today!

Ready, rock-paper-scissors! It's a draw!

My rock-paper-scissors is weak. I've never heard of a sure fire way to win.

I'm no good at rock-paper-scissors. I wonder if there's some sort of winning strategy to it.