Manifold

One of the oldest known card games on Aiaos, Manifold is a score-counting showdown game for two players.
Each player is dealt a hands of five from a Manifold Deck. An eleventh card is placed face down in the middle of the table; this is called the post.
The first player places a stake or passes. If they pass, the second player can either place a stake, or pass. If both players pass, the cards are discarded and another hand can be dealt.
Once a player stakes, the two take turns to match, double or decline.
When a player matches they add money to the pot to equal their opponent's current stake and place one of their cards face down on the table in front of them. The cards face down at any time are called the catch.
When a player doubles, they add money to the pot to double their opponent's current stake and may choose to either discard a card, face down, and draw another from the deck, or take one of their cards from the catch back into their hand. If only a single card remains in the deck - usually only happens with twenty-two card decks - the player must match.
When a player declines, they return their hand and catch to the deck without revealling them. Their opponent takes any stake in the pot.
When either both players match in turn, or one player has five cards in their catch, both players reveal their cards and the post is turned face up.
If the post is revealled to be the Tomb, the pot is retained and a new hand is dealt; otherwise the player with the highest scoring hand takes the pot.
To score a hand, the player adds the values of their five cards, and adds the value of the post for each card in their hand that matches its colour or suit.