Houserule Gambling

Gambling
Games of Skill
Games of skill always require some skilled training on the part of the player. To reflect this, each such game generally has a Tool Proficiency associated with it, reflecting not only knowledge of the game's rules but also experience playing it and an understanding of the principles at work. Each game can entertain a variable number of players, and each game uses one or two specific Abilities in checks involving that game.
Talis: There are many games played using the talis deck, including whist, poker, talison, elemental empires, and old wizard. Of these, whist (4 players, in teams of 2; Wisdom or Charisma) and poker (2 to 7 players; Intelligence or Wisdom) are most often played at the gambling table, though talison (2 to 6 players) occasionally sees play in some upper class establishments.
Darts: A game of darts thrown at a delineated target board in the back of a hall, with a scoring system based on those who manage to get closest to the center of the target, or who manage to lay down specific patterns of scoring on the board. (2 to 4 players; uses weapon or game proficiency; Dexterity)
Billiards: A game that uses a specialized felt-covered table, with balls struck around the table using cue sticks. (2 players; Dexterity or Intelligence)
Table Dice: Also known as backgammon, this is a game that combines dice rolls with tactical draughts. (2 players; Wisdom)
Tiles: A game played with a system of numbered, interlocking tiles creating cascades of points. (2 to 4 players; Intelligence)
Games of Chance
Unlike games of skill, there is no proficiency involved with games of chance. The mechanisms for resolution are entirely luck-based, with winning based on just how fortunate the player is. To reflect play of these games, each participant rolls a single d20, with the highest result winning.
Dice: There are a variety of dice games, all of which basically involve the rolling of specific lucky combinations of dice. A wide variety of dice are used for myriad games, including snake eyes, fallen temple, dragon dice, and gemstones are just a few of the games played.
Random Numbers: Various methods of betting on randomly generated numbers coming up, whether chits or balls drawn from a bag, numbers rolled on dice, or numbers spun on a wheel.
Cheating
With good coin often up for winning, it is inevitable that those who play these games will attempt to rig them, so as to ensure a payoff. There are many methods for cheating at games. By and large, they inevitably involve the use of sleight of hand.
As such, if a player makes a successful Dexterity (Sleight of Hand) test when playing a game of skill
Games of Skill: If successful, the cheater may make their game-play check at advantage.
Games of Luck: If successful, the cheater's opponents make their game-play checks at disadvantage.
The result of this check is the DC for others to notice they are cheating, however - other players may make Wisdom (Perception or Game Tool Proficiency, whichever is better) tests to spot the cheater at work.
Tavern Games
These games are the simple tavern games that are simplicity itself to find - there is inevitably one going on in most taverns, taprooms, or ale halls at any given time. Such games include cards, dice, darts, billiards, and the like. By and large, a night's worth of tavern games is a small pot, but good for some entertainment. Generally speaking, the stakes of games at a tavern or other drinking establishment are usually based on the quality of the place.
One Coin (Squalid): Stake: 1sp. Winnings: Winner gains 5cp per point above the next highest result.
Two Coins (Poor): Stake: 2sp. Winnings: Winner gains 1sp per point above the next highest result.
Three Coins (Modest): Stake: 1gp. Winnings: Winner gains 5sp per point above the next highest result.
Four Coins (Comfortable): Stake: 2gp. Winnings: Winner gains 1gp per point above the next highest result.
Five Coins (Wealthy): Stake: 4gp. Winnings: Winner gains 2gp per point above the next highest result.
Other Gambling
Generally speaking, non-casual gaming - of the sort that occurs in casinos or at events such as horse races - is handled through the Carousing Downtime Action, as the investment of time and money into such endeavors is beyond the scope of this simple, casual system.