A game that surprisingly actually has nothing to do with poker. Liar's poker is played using only dollar bills; they don't need to be American, but they do need to have some sort of serial number on them. Ideally, each player should have a few.

Game Setup: The players stand in a circle. Each player shuffles his or her bills and fans them face down (so the serial number is hidden). Someone else picks one of the dollars at random, and then hands it back to the owner without looking at it. Thus, each player gets one randomly selected dollar.

How To Play: The point of the game is to guess how many times a particular number is present in the serial numbers of all the bills, combined. Determine who goes first in whatever manner you wish. That person then names a number of numbers, such as "One 3" or "Two 2s"; he or she is asserting that the serial numbers of all the bills collectively contain that many instances of the named number. Play moves to the left. The next player may either raise the bid or pass. If the player chooses to raise the bid, they must call out the same number of instances of a higher number, or a higher number of instances of any number. For example, if the previous call was "Two 3s", the next player could say "Two 4s" or "Three 2s", but could not say "Two 2s." Zeroes are counted as ten for this purpose. Once the player has chosen to raise the bid or pass, play continues on to the left.

Winning And Losing: Once someone has made a bid, and everyone else has passed, so that play comes back to the bidder with the bid unchanged, it is time to check the serial numbers on all the bills. If the bidder is correct -- that is, if there are at least as many instances of the specified number as claimed -- the bidder wins each dollar used. If the bidder is wrong -- that is, if there are not as many instances of the specified number as claimed -- the bidder owes each player a dollar. The game repeats as desired.

The game is easy to learn, and can be played just about anywhere; nearly everyone has a few dollars on them. A game is typically over with in less than a minute.

Bluffing is of utmost importance in this game, which is why it's called Liar's Poker. Even if you're lucky enough to have a bill that has three of a specific number, bidding that number early or strongly gives information to other players that they may be able to use against you. Conversely, bidding a number you have none of may trick an opponent into overestimating how many instances of that number exist, causing them to bid too high.