A game is a structured form of play, usually undertaken for enjoyment and sometimes used as an educational tool.Games are distinct from work, which is usually carried out for remuneration, and from art, which is more often an expression of aesthetic or ideological elements. However, the distinction is not clear-cut, and many games are also considered to be work (such as professional players of spectator sports or games) or art (such as jigsaw puzzles or games involving an artistic layout such as Mahjong, solitaire, or some video games). Games are sometimes played purely for entertainment, sometimes for achievement or reward as well. They can be played alone, in teams, or online; by amateurs or by professionals. The players may have an audience of non-players, such as when people are entertained by watching a chess championship. On the other hand, players in a game may constitute their own audience as they take their turn to play. Often, part of the entertainment for children playing a game is deciding who is part of their audience and who is a player. Key components of games are goals, rules, challenge, and interaction. Games generally involve mental or physical stimulation, and often both. Many games help develop practical skills, serve as a form of exercise, or otherwise perform an educational, simulational, or psychological role. Attested as early as 2600 BC,games are a universal part of human experience and present in all cultures. The Royal Game of Ur, Senet, and Mancala are some of the oldest known games.

Ludwig Wittgenstein
Ludwig Wittgenstein was probably the first academic philosopher to address the definition of the word game. In his Philosophical Investigations,Wittgenstein argued that the elements of games, such as play, rules, and competition, all fail to adequately define what games are. From this, Wittgenstein concluded that people apply the term game to a range of disparate human activities that bear to one another only what one might call family resemblances. As the following game definitions show, this conclusion was not a final one and today many philosophers, like Thomas Hurka, think that Wittgenstein was wrong and that Bernard Suits' definition is a good answer to the problem.

Roger Caillois
French sociologist Roger Caillois, in his book Les jeux et les hommes (Games and Men),defined a game as an activity that must have the following characteristics: fun: the activity is chosen for its light-hearted character separate: it is circumscribed in time and place uncertain: the outcome of the activity is unforeseeable non-productive: participation does not accomplish anything useful governed by rules: the activity has rules that are different from everyday life fictitious: it is accompanied by the awareness of a different reality

Chris Crawford
Computer game designer Chris Crawford, founder of The Journal of Computer Game Design, has attempted to define the term game using a series of dichotomies: Creative expression is art if made for its own beauty, and entertainment if made for money. A piece of entertainment is a plaything if it is interactive. Movies and books are cited as examples of non-interactive entertainment. If no goals are associated with a plaything, it is a toy. (Crawford notes that by his definition, (a) a toy can become a game element if the player makes up rules, and (b) The Sims and SimCity are toys, not games.) If it has goals, a plaything is a challenge. If a challenge has no "active agent against whom you compete", it is a puzzle; if there is one, it is a conflict. (Crawford admits that this is a subjective test. Video games with noticeably algorithmic artificial intelligence can be played as puzzles; these include the patterns used to evade ghosts in Pac-Man.) Finally, if the player can only outperform the opponent, but not attack them to interfere with their performance, the conflict is a competition. (Competitions include racing and figure skating.) However, if attacks are allowed, then the conflict qualifies as a game. Crawford's definition may thus be rendered as[original research?]: an interactive, goal-oriented activity made for money, with active agents to play against, in which players (including active agents) can interfere with each other.

Other definitions
"A game is a system in which players engage in an artificial conflict, defined by rules, that results in a quantifiable outcome." (Katie Salen and Eric Zimmerman)
"A game is a form of art in which participants, termed players, make decisions in order to manage resources through game tokens in the pursuit of a goal." (Greg Costikyan)[10] According to this definition, some "games" that do not involve choices, such as Chutes and Ladders, Candy Land, and War are not technically games any more than a slot machine is.
"A game is an activity among two or more independent decision-makers seeking to achieve their objectives in some limiting context." (Clark C. Abt)