As computer game studies mature as a field, it requires a theoretical foundations and a conceptual framework. Activities in games appear to be constructive in the sense that learners build their own understanding of knowledge while gaming. Activity theory is broadly defined as a philosophical and cross-disciplinary framework for studying different forms of human practices as development processes, simultaneously linking individual and social levels. Human activity, according to the theory, has six components the subject, the object, its tools, its rules, the community, and the division of labor. Using activity theory as a framework for understanding activities in games necessitates the clarification of the goal and the six components of activity systems: the subject, the object, its tools, its rules, the community, and the division of labor. The subject is a player who is participating in the game. The object is the content that the educational game designer intends learners to learn while they play their games. The tools are computer, network and educational game software etc. The communities are friendly forces or enemies in games. The rules are the game rules or rules under which they negotiate. The division of labor is horizontal division of tasks or vertical division of power and status. Educational game designers should follow the players activity system in the context of real problem solving. This will ensure the meaningfulness of the educational game software.