Games are sometimes played purely for enjoyment, 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. A toy and a game are not the same. Toys generally allow for unrestricted play whereas games come with present rules.

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, or psychological role.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 realityMany sports require special equipment and dedicated playing fields, leading to the involvement of a community much larger than the group of players. A city or town may set aside such resources for the organization of sports leagues.

Popular sports may have spectators who are entertained just by watching games. A community will often align itself with a local sports team that supposedly represents it (even if the team or most of its players only recently moved in); they often align themselves against their opponents or have traditional rivalries. The concept of fandom began with sports fans.

Card games use a deck of cards as their central tool. These cards may be a standard Anglo-American (52-card) deck of playing cards (such as for bridge, poker, Rummy, etc.), a regional deck using 32, 36 or 40 cards and different suit signs (such as for the popular German game skat), a tarot deck of 78 cards (used in Europe to play a variety of trick-taking games collectively known as Tarot, Tarock or Tarocchi games), or a deck specific to the individual game (such as Set or 1000 Blank White Cards). Uno and Rook are examples of games that were originally played with a standard