My parents were in town last weekend and taught the kids "rock, paper, scissors" during their afternoon together. The kids love these kinds of quick games with no parts to fetch or lose and were immediately sucked into playing for hours.
On Friday I was at the kids' school and happened to be standing next to a large group of the pre-k kids waiting in a line. Several kids had turned to each other in line and started games of rock, paper, scissors while sat on the benches. I suspected Jorge had shown some friends and finally asked tonight. Yes, he had taught a rather large group of the kids at recess one day and was the ring leader of the rock-paper-scissors gang. It had spread like a virus through all four pre-k cottages. 100+ kids chanting "Rock, paper, scissors, SHOE."*
*Only tonight did we notice they were saying "Shoe" instead of "shoot," and then only because Katie turned to us to ask how to make the hand sign for shoe.
And, yes, as true geeks we have looked up the rock-paper-scissors-lizard-spock version from BBT but the kids are pretty happy with the traditional version.