This is a kind of competitive patience (solitaire) game for two players. It is also known as Cat and Mouse. Both players try to be the first to get rid of a pile of "pay-off cards" by playing them to centre stacks which are begun with an ace and continue in upward sequence to a king. This is not a physical race (as in Spit or Racing Demon where play is simultaneous) - in Spite and Malice the players take turns.
There are quite a few different versions of Spite and Malice around. First I will give what seems to be the most widely played version of the game. Then I will describe some of the more popular variations, and finally I will explain the rather different version which appears in most of the card game books.
Spite and Malice was originally a two player game, and it is easiest to describe this version first. Versions for larger numbers of players are described later. Two 52 card packs of cards are needed. The cards in each pack rank from low to high: A-2-3-4-5-6-7-8-9-10-J-Q, with kings wild. Suits are irrelevant in this game.
The layout of the game is shown in the following diagram:
To begin the game both packs are shuffled together and 20 cards are dealt face down to each pay-off pile, and a further 5 cards are dealt to each player as their hand. The remainder of the cards are placed face down between the players to form the stock. The top card of each pay-off pile is turned face up and placed on top. Whichever player has the higher card showing will play first. If they are equal, both players shuffle their pay-off piles and turn up a new top card. At this stage the centre stacks and side stacks are all empty.
The object of the game is to be the first get rid of all the cards in your pay-off pile by playing them to the centre stacks. Only the top card of your pay-off pile is available for play at any time; when you have managed to get rid of the top card, you turn the next pay-off card face up and try to get rid of that.
The first card in each centre stack must be an ace, then 2, 3, and so on in sequence up to queen, each card played being one higher than the card it covers. There cannot be more than three centre stacks at one time.
The side stacks can contain cards in any order, and when playing to a side stack you may put your card on whichever stack you choose. The only limitation is that you cannot have more than four side stacks.
The player whose first pay-off card is higher plays first, and thereafter the players take alternate turns. If you have fewer than five cards in your hand you begin your turn by drawing cards from the stock to bring your hand up to five cards. You may then make a series of moves, the possible moves being:
You may play as many cards to the centre stacks as you want, but as soon as you play a card to a side stack your turn ends, and your opponent may play.
Note that you can never play a pay-off card to a side stack, or to move a card from one side stack to another, or move a card from a centre stack to anywhere.
Kings are wild and can represent any card. You can discard a king to a side stack without committing yourself as to what it represents. When a king is placed on a centre stack it represents the next higher value than the card it covers.
If during your turn you manage to play all five cards from your hand, without playing to a side stack, you immediately draw five more cards from the stock and continue playing.
If you complete a centre stack by playing a queen (or a king representing a queen) your opponent shuffles the completed stack into the stock, creating a space for a new centre stack, and you can continue playing.
The game ends when someone wins by playing the last card of their pay-off pile to the centre. The game can also end if the stock runs out of cards, in which case the result is a draw.
Spite and Malice can easily be adapted for any number of players. Turn to play passes clockwise. Depending on the number of players and how many cards you deal to the payoff piles, more decks may need to be added - for example some play with one deck per player. Some play that the number of centre stacks is limited to one more than the number of players - i.e. four for three players, five for four players, etc.
Four people can play as partners; six people form three teams of two. Partners sit opposite each other. At your turn you can play from your partner's pay-off pile or side stacks to the centre stacks, but you can only discard to your own side stack. Play continues until one pair wins by playing all the cards from both of their pay-off piles.
Some players allow an unlimited number of centre stacks (but never more than four side stacks for each player). In this case it is not necessary to remove completed centre stacks immediately, but you may agree to wait until the stock is depleted.
Some play other limits on the number of centre stacks - for example a maximum of four.
Some play that aces cannot be retained in your hand but must be played as soon as drawn to start new centre stacks. Also an ace appearing on your pay-off pile must immediately be played to the centre. In this version there is no limit on the number of centre stacks.
In this variation, reported by Henry Lee, it is permissible to move the card from the top of your pay-off pile or play a card from your hand onto the top of your opponent's pay-off pile. The card must be the same suit and one rank higher or lower than the card on which it is placed. For example if the top card of your opponent's pay-off pile is a 
8 you can load a 9 or a 7 onto it. It is sometimes possible to give your opponent a series of cards in this way. Note that you are not allowed to load cards from your discard piles onto your opponent's pay-off pile - the card must come from the top of your own pay-off pile or out of your hand. (Since this version is played with unlimited centre stacks and compulsory play of aces, the question of whether aces can be loaded on kings or vice versa does not arise.)
Some people play with a different number of cards in the initial pay-off piles - for example 21 or 25.
Some people play that if the stock runs out the winner is the player with fewest cards remaining in their pay-off pile. Only if the pay-off piles have equal numbers of cards is the result a draw.
Some people include jokers in the deck for Spite and Malice. The jokers are wild and can represent any card. Some play that the kings remain wild as well; others play that only the jokers are wild, and that 13 cards are needed top complete each centre stack, ending with the king.
Some play that a wild card (King, or Joker if used) cannot be used to represent an ace. Others play that a wild card cannot represent an ace or a seven.
Jeffrey Jacobs suggests that if a series of games is played, the same scoring system as in the "book version" below can be used. (The proprietary game Skip-Bo also uses a similar system.) The winner of a hand scores 5 points for winning the hand plus 1 point for each card left in the opponent's pay-off pile. For example, if you win and catch your opponent with six cards, you score 11 points (5 for winning the hand plus 6 for cards). In a stalemate the player with fewer cards scores the difference between the numbers of cards each player has left. The winner could be the first player to reach a target score, such as 50.
Benjamin Arnoldy has reported a rather different version of the game, played in Massachusetts. The main differences are:
When Spite and Malice is found in card game books, the versions described are normally rather different from the one described on this page. The main differences in the book version are as follows.
With Mari J Michaelis's SpiteNET: Spite and Malice computer program you can play against the computer or against a live opponent over the Internet.
The collection HOYLE Card Games for Windows or Mac OS X includes a Spite and Malice program, along with many other popular card games.
Games4All has published a free Spite and Malice app for the Android platform.
Net Spite and Malice, from NetIntellGames, also allows you to play against a computer opponent or with a human opponent over a network.
Mike Perry has written a Cat and Mouse (Spite and Malice) program for the Mac.
The German site Skill 7 includes an online Spite and Malice game under the name "Katz und Maus".
From the Tams11 lobby you can obtain an Windows Snerks game (similar to Spite and Malice) that can be played solo or on line against a live opponent.
At Solitaire Online you can play Spite and Malice online against the computer.