Zendo is a game where you use your brain to figure out the rules of a secret thing called a "koan." A "koan" is an interesting puzzle that can be done just by looking at things.
One person is chosen to be the "Master," and they make a secret koan in their head. They then build a bunch of structures out of special blocks called "Pyramids" using clues that follow the rules of the koan.
The other people playing the game try to guess the rules of the koan by looking at the structures the Master has built. They guess what the rule might be by building their own structure out of Pyramids, putting them in the middle of a table, and then ask the Master if their structure follows the rules of the koan or not. The Master will then give hints or clues to help the guesser figure out the rule of the koan.
Once someone figures out the rule of the koan, they are the winner! The game is a fun way to use your brain and learn how to figure out tricky puzzles.