Zendo comes with 40 rule cards that generate over 200 unique rules. That'll keep players guessing for a long while, but when you're ready for more, here's a set of 10 secret rule cards: one rated as Easy, four as Medium, and five as Difficult. These cards will generate 52 different rules, but don't let anyone read these cards until someone is ready to moderate a session. The fun is in figuring it out, so please keep the secret rules secret.