Rock Paper Scissors Comes From the 3rd Century
What happens when you and a friend are faced with a decision and are unable to agree? You resolve it as grownups would. Rock, Paper, Scissors is what you do. It's the traditional method of choosing a winner in any circumstance, relying mainly on luck, fate, or an accurate understanding of your opponent's preferences.
If the movie is any indication, the game appears to be one of those things that gained popularity in the 1960s or 1970s, but that is wildly inaccurate. The World Rock Paper Scissors Association, a legitimate organization, provides a comprehensive history of the game on their website.
In actuality, Rock, Paper, Scissors dates back to China's Han Dynasty, which lasted from roughly 206 BC to 220 AD. Back ago, it was known as shoushiling, which, depending on your source, either meant "hand command" or "three who are scared of one other." Although you weren't literally playing rock, paper, scissors with your hands—that was a later invention in Japan—the game's concept was the same. In the original edition, you may choose to play Snake, Slug, or Frog. Snake defeats slug, frog, and slug.