This course explores worldbuilding (the creative process and structures through which an imaginary world is created, maintained, and expanded) through the worlds created in video games. Video games are a multi-billion dollar-per year global industry and have a significant impact on our society. Video games offer us a multitude of alternative worlds into which we can not only escape our world for a few hours at a time, but build communities in our world tied together by shared love of a game's world. Many well-built game worlds rely on conventions such as narrative, character development, and plot to carry us through their worlds. However, worldbuilding elements such as cultures, ecologies, histories, geographies, governance, and religious and magical systems enliven a game, absorb our attention in the story world, and invite us to imaginatively fill gaps in the game world. Further, a well-crafted game with a well-built game world can spill over into our primary world. It can shape popular culture, fuel speculation on social media, invite fans to write their own stories, cosplay as characters in that world, or even create mods to expand the game world. In understanding the ways worldbuilding elements create imaginary and immersive realities, we can better understand the creative process behind such works and, perhaps, gain insights into how we understand our real world.