A game system is a set of components that function together in multiple games. The StandardDeckOfCards familiar to almost everyone is a game system because it is a set of components (52 of them, 54 with jokers) that function together (a lone Jack of Hearts isn't very useful except to college sophomores as a poetic metaphor) in multiple games (such as Poker, Patience, Pinochle, and the weird concoctions of Parlett and Abbott).
Ron_Hale-Evans? has written a series of articles on game systems for The Games Journal that he is collating into a book. There are four articles in the series so far, with more to follow:
Game Systems, Part 1: Introduction
Game Systems, Part 2: Card Game Systems
Game Systems, Part 3: Board Game Systems
Game Systems, Part 4: Low-Tech Game Systems
The articles in this series have been popping up in academia:
Ron's more recent pieces about game systems are available at his blog.
See also CategoryGameSystemPage? for a list of game systems known to this Wiki.
These are excellent articles. I am looking foward to the next ones.--IainCheyne?