Like many card games there are several variations on the rules, but the most popular version (4-player with standard rules) will be described below:
The game is played with a deck of 43 cards - 2's, 3's, and red 4's are removed from the deck, and a joker is used. Players play in pairs, with paired players usually placed diagonally opposite to each other. To begin a hand, ten cards are dealt to each player, and the remaining three cards (known as the "kitty") are placed in the centre of the table. Traditionally, the deal is performed by dealing three cards to each player, then placing a card in the kitty, four cards each and one to the kitty, and then three and one to the kitty.
After the deal, players "bid" in turn. A bid indicates that the player has agreed, if no higher bids are made, that they will attempt to win a certain number of "tricks" and that a certain suit will be "trump" for this hand. For instance, a bid of "6 spades" indicates that the player wants to attempt to win 6 or more tricks with spades being the "trump" suit. The player may elect not to bid - also called "passing". Bidding proceeds clockwise around the table, and each subsequent bid must be a higher-scoring bid (see the scoring table below) or the player must pass. If a player passes, they cannot subsequently make a bid in this hand. Eventually, all but one player will pass and the bid is decided. The player making the successful bid then collects the kitty. This player then sorts through his hand and discards the least useful 3 cards (possibly including cards picked up from the kitty), and places them face down, the discarded cards playing no further part in the hand.
Ten tricks are then played. The person who won the previous trick (or, for the first trick, the person who made the successful bid) places a card, face up, into the center of the table. Each player, clockwise, in turn, must also put down a card. If they have cards of the same suit, they must put down one of those, otherwise they can put down any card they choose. After all players, the person with the highest card (card order is discussed below) wins the trick. This fact is recorded, and the player that won the trick then starts the next trick.
Determining who has played the highest card is a little complex. The Joker is always the highest card, and adopts the identity of the trump suit for that round (so, if the joker is the card "led", all players must play a card of the trump suit if they have one, and if the player holds the joker and no other cards of the trump suit, and the trump suit is led by another player the joker must be played). The next highest card is the Jack of the trump suit (the "right bower"), then followed by the Jack of the other suit of the same colour (the "left bower", which for this hand becomes a member of the trump suit just like the joker), then the Ace, King, Queen, 10, and the picture cards of descending order in the trump suit. If a suit other than the trump suit was "led", the trump suit cards remain highest as described (but can only be played if the player has no cards in the suit that was led), then cards of the led suit (in conventional Ace, King, Queen, Jack (unless the Jack of that suit is a bower for this hand), 10 . . . order). Cards of suits other than the led suit or the trump suit can obviously never win a trick.
After all ten tricks have been played, the number of tricks won by each pairing is tallied up. If the pairing of the player that made the successful bid makes their bid, they are awarded points according to the table below. If they do not, that number of points are subtracted off their score. The other pairing is awarded ten points for each trick that they won. A team that scores 500 points by bidding and making their target wins the game - any scoring by the 10-points-per-trick rule that puts you over 490 points is immediately rounded down to 490 again. A team whose score dips below -500 points loses the game.
There are two sorts of "special" bids. "No trumps" bids mean just that, there is no trump suit, and no bowers. When the joker is played, its suit may be nominated. However, it may only be played as the first or last card in the suit - playing a card of a particular suit, then the joker (and calling it that suit), then another card of that suit, is not permitted. No trumps is more difficult to play successfully than conventional hands. Misere is a variation of "no trumps" that can only be bid once a bid for seven tricks has been made by another player. In misere, the player's partner drops out of the hand, their cards left face down on the table and unplayed. The remaining player must *lose* every trick. The joker remains the high card. "Open misere", which can only be bid after an eight-trick bid, is identical, except that after the first trick is played the bidding player must place all their remaining cards on the table and play out the hand with the other players knowing the bidder's cards.
The scoring table is as follows:
Misere: 250 Open Misere:500
If a team wins all 10 tricks and your bid scores less than 250 (or did not bid) the team gets 250 points.
If nobody makes a bid, there are two variations. Most commonly, the hand is declared dead and a reshuffle and redeal is made,but some games are played where no bids means the round is played as no trumps, and scoring is 10 points per trick.
Misere and open misere rules are subject to some variation, as experienced players find them much easier to achieve than similarly-scored conventional hands. One variation involves standard misere being banned, open misere's score being reduced to 230 points, and new type of misere hand, "super open misere", worth 430 points, is introduced, where after the first trick is played, the opposing team not only sees the bidder's cards but plays them for them in an attempt to force them to win a trick (and thus lose the hand).
Variations in the number of players require a variation in the number of cards in the pack. 6-player 500 requires a special 63-card pack (with 11, 12, and red 13-spot cards).
500 is largely a social game, and has not attracted the deep tactical analysis of bridge. Tactics often revolve around using various means to indicate to one's partner information about the hand one possesses, including agreements to make certain bids depending on whether one possesses specific cards (rather than on what the player believes they can realistically win), and surreptitious signals (by the tone of voice, exact words used to indicate bids, and so on).