Only a limited number of research studies have investigated how students design educational computer games and its impact on student learning. In addition, most studies on educational game design by students were conducted in the areas of mathematics and science. Using the qualitative case study approach, this study explored how seventh graders created their own computer games on the topic of the containment of communism and what they learned from the game design and playtesting processes. This study also examined the impact of the game design experience on the students' interest and motivation. Twelve students, eight boys and four girls, participated in the study. Qualitative data were collected from multiple data sources, including classroom observations, participants' games, playtest feedback forms, reflection sheets, and interviews. The results showed that most students were highly engaged in the game design task. They used their sprites creatively to create objects or environments related to the historical events. The game design project enabled the students to experience what it is like to be a game designer. The students learned the value of diverse perspectives from the playtesting and feedback process. They also learned to consider the player's perspective when designing a game. The game design experience motivated several students to learn more about game design or programming.