Rationality Cardinality consists of two types of cards, Question cards and Answer cards. Each round, one player is the judge; they draw a Question card and read it to the other players, who pick one of the ten Answer cards from their hand and play it face down. One random card is added to serve as the control player, and the cards are shuffled together. The judge reads the cards and picks their favorite, and the player who submitted it gets a point. The cards themselves are part nerd humor and part teaching material: they take concepts from rationality, philosophy, economics, and other fields, make them into jokes, and provide captions to explain the meaning.