A game is a structured or semi-structured activity, usually undertaken for enjoyment and sometimes also used as an educational tool. (The term "game" is also used to describe simulation of various activities e.g., for the purposes of training, analysis or prediction, etc., see "Game (simulation)".) Games are generally distinct from work, which is usually carried out for remuneration, and from art, which is more concerned with the expression of ideas. However, the distinction is not clear-cut, and many games may also be considered work and/or art. 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.
Known to have been played as far back as prehistoric times, games are a universal part of human experience and present in all cultures.
source: www.wikipedia.org