Just as rax said, you can play Briscola for two, which is perfectly acceptable, though it gets a little dull. However, this node would be woefully incomplete if I didn't also mention that there are many different versions of Briscola, most of which are played with larger groups.
Before I get into that, though, I should clarify something else that was mentioned. Briscola is indeed usually played with a traditional 40-card Italian deck, which I highly recommend, because it will cut down on confusion once you learn it. (For instance, the threes are larger and more stylized, since they are almost as important as aces, unlike in American card games where threes are just like any other number card.) An Italian deck contains 4 suits: coins, cups, clubs and swords. Each suit contains cards numbered 1 through 7, plus three face cards: re, a man wearing a green crown (equiv. to a King); cavallo, a man with a yellow hat riding a horse (equiv. to a Queen); and fante, a girl with red hair or wearing a red hat (equiv. to a Jack). The cards themselves are smaller than typical Poker cards, usually 5 cm x 8 cm. The best decks are made by a company called Modiano.
Anyway, back to what I was saying about multi-player Briscola. There are four other widely-played versions of the game besides the simple two-player setup:
I'll start with the simplest version, Briscola for 3, which for the most part plays exactly like the 2-player game. There are a few obvious differences, though. First of all, you don't want an even number of cards, so take out the two of coins. Secondly, since the tricks (and the points) are now being distributed three ways, you no longer need more than 60 points to win; in this case, the person with the most points at the end of a round wins (note: that means the lowest possible winning score is 42). Play proceeds counter-clockwise.
Next, there's 4-man Briscola, by far the most popular version of the game. Four-player is very much like three-player, except that you play with a full deck of 40, and the pairs sitting across from each other are considered partners (like in Euchre) and pool their points. Unlike in Euchre, however, "table talk" (that is, discussing the contents of your hand) is perfectly legal. More experienced players may even signal each other with surreptitious gestures instead of speaking openly. This eventually leads to constant strategizing, with teams trying to plan out moves while at the same time trying to crack the other teams codes. Though it sounds daunting, the basic strategy is still fairly simple. If you've got points, you want to tell your partner to throw trump on it, and vice versa. The higher the points, the higher the trump, since the other team is naturally going to try their best to steal them.
There's also a six-player Briscola that plays very similarly to the four-player game. The only differences here is that, in order to get even hands, you need to reduce the deck to 36 cards by taking out all the twos. This version has 2 three-person teams, arranged such that the teams are alternating (in other words, when counting in a circle, the 1st, 3rd and 5th seats are one team, the 2nd, 4th, and 6th seats are the other). 6-man Briscola is known for having even more complex hand-signals and strategy, and (since there's less cards and more players holding them) much faster rounds.
Lastly, there is a 5-player version of the game called--- no joking--- Bastard Briscola. Though it differs quite a bit from the typical game, with the right people this version is a riot. The basic rules of the game remain (i.e. the object is to get the highest points, trump overrides other suits, etc). However, the rules change in three very drastic ways...
- The Deal. Instead of only three cards per person, the entire deck is dealt out at the beginning of each round, leaving each of the five players with a fat hand of 8 cards. Notice that there aren't any cards left to turn-up; instead, trump (briscole) is determined by...
- Bidding. At the beginning of each round, beginning with player to the right of the dealer, each player makes a bid as to how many points his team will try to take in the round. Each consecutive player must then either raise the bid, or else choose to pass and drop out of the bidding. Bidding proceeds counter-clockwise until one player is left with an unchallenged high bid.
Having the high bid grants that player ("the caller") two very important rights. First of all, he has the right to decide which suit is trump for that round. Second of all, he earns the right to call out the name of a card (for instance, "Ace of Clubs"). For the rest of that round, the player that has the card that was called will secretly become the "bastard" (or, in more polite company, the "holder") and is on the same team as the caller. The three other players form a team that is trying to stop the caller/bastard pair. The trick is: no one, not even the person who called the hand, knows for sure which player is the bastard (heh), until the card that was called (e.g. the "Ace of Clubs") is actually played. Up until that point, each player gathers their tricks separately, and massive amounts of bluffing, lying and back-stabbing ensue.
(Note that a caller may actually choose to call a card in his own hand. This is the equivalent of "going alone" in Euchre, except that not only do you lose the benefit of a partner, but the person who was going to be your partner is now playing against you.)
- Scoring. At the end of the hand, the points scored by the caller and the bastard (or, just the caller, if he chooses to go alone) are added up. If the total is equal or higher to what was bid at the beginning of the round, the caller receives 2 points, the bastard receives 1 point, and the other three players are set back by -1. If the total is less than the bid, each of the three players recieves 1 point, the caller is set back -2, and the bastard is set back -1. If it turns out that the caller chose to go alone, and he still made his bid, then he receives 4 points, and the other four players are set back -1 each. However, if the caller chose to go alone and missed his bid, he's set back -4, and the other players get 1 point a piece. Games are usually played to 10 or 15, but they can really go on as long as you like.
One last note: It is very difficult to cheat at Briscola. This is good, because most of the Italians I've known take the game very very seriously. ;o)