I like this definition of a game:
Wikipedia Wrote:Computer game designer Chris Crawford, founder of The Journal of Computer Game Design, has attempted to define the term game[8] 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.