Mafiopoly is not a stand-alone game, but a deck of cards and set of optional rules to be added to Parker Brothers' Monopoly board game. Players are given the option of playing as a Mafia player (Mafioso) or a regular player (Citizen). Citizens play by the normal Monopoly rules while Mafiosi draw from the Mafia Card deck every time they pass Go. Mafiosi also have other special rules, such as the ability to grift $50 from the bank every time any player passes Go. These advantages are somewhat balanced by the innate dangers of the profession: the Mafia Cards may cause a player to fall under investigation by a Federal Grand Jury or fall victim to as assassination attempt. One of the other Mafioso players may even put out a hit on you!
There is an interesting optional rule that allows any Mafiosi to cheat, as long as they don't get caught. If they get caught, they must pay 10% of their holdings to the bank and 10% to the player who blew the whistle.