Fictional universe of Harry Potter Harry, serves as the commentator for the Quidditch matches at Hogwarts until he graduates. The sport appears in every book except the seventh; school matches are canceled in the fourth due to the need to use the pitch for the Triwizard Tournament, but Harry attends the Quidditch World Cup as a guest of the Weasley family. Other wizard games and sports include Gobstones (a version of marbles in which the stones squirt foul-smelling liquid into the other player's face when they lose a point), Exploding Snap (a card game in which the cards explode), and Wizard Chess (in which the
Harry Potter and the Methods of Rationality of "HPMOR" spontaneously burped itself into existence inside my mind, so it came out as a Harry Potter story. ... there's a large number of potential readers who would enter at least moderately familiar with the Harry Potter universe." He states that his work on rationality "informs every shade of how the characters think, both those who are allegedly rational and otherwise". He also used it to assist the launch of the Center for Applied Rationality, which teaches courses based on his work. Unlike J. K. Rowling's original books, in which the orphaned Harry Potter is raised by the abusive