A game is a structured or semi-structured recreational activity, usually undertaken for enjoyment (although sometimes for physical or vocational training). A goal that the players try to reach and a set of rule concerning what the players can or cannot do create the challenge and structure in a game, and are thus central to its definition.

Known to have been played as far back as prehistoric times, games are generally distinct from work, which is usually carried out for remuneration. Because a wide variety of activities are enjoyable, numerous types of games have developed.

What creates an enjoyable game varies from one individual to the next. Age, understanding (of the game), intelligence level, and (to some extent) personality are factors that determine what games a person enjoys. Depending on these factors, people vary the number and complexity of objectives, rules, challenges, and participants to increase their enjoyment.