Dragonchess

"The playing surface for DRAGONCHESS is a three-tiered structure of rectangular boards, with each board composed of a grid 12 squares wide and 8 squares deep. The squares are alternately colored light and dark (or other color tones that contrast with each other), configured so that a light-colored square is in the near right-hand corner when the board is viewed from the longer side. The upper board represents the air, the middle board the land, and the lower board the subterranean world. To simulate the various environments, it is suggested that the squares on upper board be colored light blue and white; on the middle board, light green and amber; and on the lower board, red and brown. Each board is the starting place for pieces particular to its environment; some pieces cannot move up or down off the board they begin on, but other pieces can travel between two or even all three boards. The opposing forces are designated as Gold and Scarlet, with Gold always moving first."
The game of Dragonchess is woven throughout the campaign. There are no Harry Potter style chess matches where players represent pieces and play by the chess rules, but in Diamond Lake, Lazare's House is a gaming parlor where Dragonchess is often played. In fact Lazare was a Dragonchess champion in the Free City some years ago and used those winnings to set up in Diamond Lake. Allustan is a Dragonchess player, as is the rival adventuring mage Khellek, and Dragonchess references pop up throughout the campaign.
Players who take a gaming set as part of their background can take Dragonchess as their specialty. Dragonchess games focus on Intelligence, although charismatic players come up with a surprise or two when playing.
A basic Dragonchess game with chits instead of carved tokens and a collapsible board costs 1 gp. Serious players will often splurge for a carved set and a permanent board, which costs 5 - 10 gp. The serious (and wealthy) player could spend much more than this for a true masterwork set with some sets costing hundreds of gold.
Another game that is referenced is the card game, Three-Dragon Ante, though it doesn't get the attention in story that Dragonchess garners.
Note: I have the Dragonchess article from Dragon #100 and will probably post the full "rules" before long.

by Gary Gygax
Dragon Magazine #100
"The DRAGONCHESS TM game is a fantasy-based variation of chess, in which the object of the game (as in standard chess) is to checkmate the opposing King. An understanding of the rules of chess is helpful in order to understand how DRAGONCHESS is played.