Haggle is a party game designed by Sid Sackson and intended for a large number of players.
At the start of the game, each player receives a secret, random, collection of plain, colored cards plus one or more slips, each one explaining one of the many valuation rules.
The players are given a particular amount of time - anything from twenty minutes to the whole party - to mix with each other.
Before the end of the game, each player is required to hand in their final card collection in an envelope.
The game very strongly encourages people to mix with each other, but is rather complex for some players.