Key components of games are goals, rules, challenge, and interactivity. 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. The requirement for interactivity should put games such as jigsaw puzzles and mah-jongg solitaire into the category of solo-player puzzle rather than being a game.

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 demonstrated that the elements of games, such as play, rules, and competition, all fail to adequately define what games are. He subsequently argued that the concept "game" could not be contained by any single definition, but that games must be looked at as a series of definitions that share a "family resemblance" to one another.

Roger Caillois

• 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 is not productive
• 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 attempted to define the term game

1. Creative expression is art if made for its own beauty, and entertainment if made for money. (This is the least rigid of his definitions. Crawford acknowledges that he often chooses a creative path over conventional business wisdom, which is why he rarely produces sequels to his games.)
2. A piece of entertainment is a plaything if it is interactive. Movies and books are cited as examples of non-interactive entertainment.
3. 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.
4. 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. Some games with noticeably algorithmic artificial intelligence can be played as puzzles; these include the patterns used to evade ghosts in Pac-Man.)
5. 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.