This thesis draws on Michel Foucault's late work on the practices of the self to ask whether the ascetic practices and patterns of action suggested by contemporary computer games, which afford players the opportunities to pursue their own self-set goals, further what might be called a 'wandering' away from ourselves, a 'transformation' or 'transfiguration' of what we are. If self-formation is now a terrain on which power and resistance plays out, it is critical to be able to identify pernicious practices that may bind us to the individualising techniques of power, as opposed to transformative ones that enable us to refuse who we are in the move towards freedom. Broaching this question leads to considerations of the implicit ethical foundations presupposed by Foucault's anti-normative ethico-aesthetics, and the limitations of its appeal to a coherence or style seemingly without rules. These considerations have implications for the way in which we understand the practices of self-constitution in computer games. I question whether there is an isomorphism between the way in which power - understood through Foucault's concept of 'governmentality' - works in the present, and the way in which computer games set the conditions under which player practices take place. We are prompted by both to develop a non-coercive relation to a 'truth' through an impetus that originates from us. Computer games are about our identification with processes, which are strengthened by the feedback loops in the game and by the mode of being we elect to adopt as a hexis. Such a structure, however, is insufficiently rigid for computer games to produce discrete subjectivities, and analyses of them must be sensitive as to whether there are any systematic concatenation of player responses. To this end, I suggest a framework, based on Foucault's orthogonal understanding of power-subject, for uncovering the 'rationalities' within games, which are the conditions under which players' practices of the self take place, and which give rise to certain practices of self-constitution over others. It depends on our being able to find or infer player typologies, which are then analysed for their similar patterns of action. This framework is applied to a case study: levelling-up in The Elder Scrolls IV: Oblivion. On the basis of six typologies, a prominent structure of calculative anticipation and deferral emerges, as well as the existence of what is called a super-instrumental approach. In order to disambiguate these findings with respect to their transformative potential, I turn to the transcendental signifiers in Foucault's work and consider the practices of the self as seeking a balance between reason and sense - they are revisited through the lens of Schiller's play drive. This concretises the argument that if the practices of the self are thought capable of moving us towards freedom, we must assume the existence of non-cognitive faculties within us that, when engaged, enable us to be able to distinguish between positive and pernicious self-formation. Given that these judgments cannot be cognitively communicated, we ought to refrain from prescriptivism, yet do have recourse to standards. However, our efforts to cognitively understand this aesthetic interplay between reason and sense are certainly not without importance.