Pineapple is similar to Holdem in using a three-card flop on the board, a fourth card, and then a fifth card. Each player is dealt three hole cards at the start. One of these cards are discarded before the flop (in regular Pineapple) or after the flop (in Crazy Pineapple). The betting is the same as Holdem. At the showdown, a player can use any combination of his remaining two cards and the board cards. A player who still has three cards in his hand at the showdown has what is called a dead hand.
Rules of Pineapple -
All the rules of Holdem apply to Pineapple. The discarding of the third card, and when it occurs, is the only difference.
Crazy Pineapple -
Crazy Pineapple is usually played high-low split, 8-or-better. A player may use any combination of two hole cards and the five board cards for the high hand and another (or the same) combination for the low hand.
If there is no qualifying hand for low, the best high hand wins the whole pot.