What happens when a player picks up video game, learns to play it, masters it, and leaves it? Using concepts from his book on video games, Half-Real: Video Games between Real Rules and Fictional Worlds, Jesper Juul argues that video game players are neither rational solvers of abstract problems, nor daydreamers in fictional worlds, but both of these things with shifting emphasis. The unique quality of video games is to be located in their intricate interplay of rules and fictions, which is examined across genres, from casual games to massively multiplayer games.Jesper Juul is a video game theorist and assistant professor in video game theory and design at the Centre for Computer Game Research Copenhagen where he also earned his PhD. His book Half-Real on video game theory was published by MIT Press in 2005. Additionally, he works as a multi-user chat systems and casual game developer. He is currently a visiting scholar at Parsons School of Design in New York.