Spades is a popular card game in America, where it was invented in the 1930s. The game works best with 4 players in teams of 2, though it is possible to play with 2 or 6 players as well. The goal of the game is to collect tricks, with spades acting as trump cards (hence the name of the game). Trump suits are those that outrank other suits regardless of the value of the cards. For example, in Spades, the 2 of spades has a greater value than an ace in any other suit.
After all the cards are dealt, players assess their hand to determine how many tricks they think they can take. Unlike other trick-taking games, the goal in Spades is not to simply collect as many tricks as possible, but rather to collect as closely as possible the amount of tricks you bid at the start of each hand. Though you play with a partner, bids are made individually based on the merit of your own hand. After you bids, your number is added to your teammate's bid. This combined number represents both the potential score for the hand, and the amount of tricks your team must collect in order to score positively. For instance if you bid two tricks and your partner bids four, you must collect six tricks between you to score (Note: teammates do not need to collect the amount of their bids individually, but simply collect the combined total). If you and your partner fail to collect your total bid, your score drops by that amount. If your team collects too many tricks (for example, you bid 5 and take 7) you collect something called a "bag," which will be explained in the scoring section.
Nil & Double Nil
When bidding, you have the option of calling zero tricks, or "nil," either before or after looking at your cards. Calling zero without looking at your cards is referred to as "double nil" or "blind nil." The goal in either case is to avoid winning any tricks, and you will be penalized heavily for collecting even one. Bidding nil is a potentially powerful--but also very risky--play. If you bid nil, you are solely responsible for not collecting tricks, i.e., your partner will still try to collect the amount of her own bid, while attempting to protect your zero call.
The player to the left of the dealer plays first, and may play any non-trump card. Play proceeds clockwise, with each player obligated to follow suit if they can. Otherwise, any card may be played, including a spade--which trumps any card, except a higher spade. Spades may not be played at the beginning of a trick, unless one has already been played as part of another trick. The winner of each trick (the player who plays the highest card, or plays the only spade) plays first on the next hand. This continues until all cards have been played.
After all the tricks are played the hand is scored. Teams receive 10 points for each trick they collect, as long as they make their total. For example, if your team bid 6 and collected 6 tricks, you receive 60 points. If your team bid six and collects only five tricks, you lose sixty points, or the entire amount of the bid. Any trick collected beyond the bid amount is known as a "bag." If your team collects 10 bags throughout the course of the game, you lose 100 points. If you call nil and collect zero tricks, your team earns 100 points, or 200 points for making a blind zero call. If you earn even a single trick, however, you lose the same amount. Play proceeds until one team reaches an amount determined in advance, usually 500 points.