This study used technology-rich ethnography (TRE) to examine the use of game development in a high school computer programming class for the development of 21st century skills. High school students created games for elementary school students while obtaining formative feedback from their younger clients. Our experience suggests that in the teaching of computer science in high schools, the development of games that include common game features such as dynamic feedback systems, backstory, levels, cheats, and compelling graphics challenges students and engages them in learning. Incorporating real client feedback is also useful for improving their work and connecting it to the "real" world. This article reports findings from the second year of a research project with a high school computer programming class. The authors argue that such approaches that leverage video games, design, programming, authenticity, and cooperation mobilize multiple 21st century skills that must be nurtured among contemporary young people so that they may grow to be part of a productive citizenry. (Contains 1 table and 3 figures.)