The article suggests an original view on the correlation between game design and jurisprudence, connected with the fact of increasing attention paid to the legal aspects of computer games in modern social sciences and humanities. First of all, law may be understood as a factor which affects game design from the standpoint of intellectual property regulation. That said, a non-trivial aspect is stressed: the process of playing is a creative process. Second, law may be viewed as a factor which determines the design content. Specific legal institutes allow including new elements of game mechanics, e. g. virtual property being traded for real money. Third (which is the most interesting), law itself can be viewed as a specific incarnation of game design (and vice versa). Both the legal system and game rules are, in essence, based on the same logic of formalized algorithms. It may be interesting to interpret game rules (above all, computer game rules) in light of the classic structure of the legal norm, which includes "hypothesis," "disposition" and " sanction," i. e. conditions whereupon the norm "fires," the behavior rule itself, and the consequences for non-compliance. The "legal norms" of a virtual world can be expressed at the level of "open" rules, which are up to players to abide by or not to abide by, and at the level of code. Each time, the designer faces the choice between leaving the rules at the level of code or bringing them up to the level of virtual social interactions. The fact of similarity between legal systems and game rules also signifies a vast creative potential, which implies that game design may borrow ideas not only from economic system, but therefore from legal systems as well.