Game Spice: Monopoly Expansion is a set of 30 new Chance Cards and 30 new Community Chest cards that replace the existing Chance and Community Chest cards. These new cards affect the game far more than the original cards. For example, various cards will allow you to steal property from other players, build houses without owning the whole color group, change your die roll, or charge an opponent double rent. One card even introduces a new victory condition.
This expansion set works with any version of Monopoly.
The author had originally planned to create additional expansions for Monopoly which could provide opportunities to buy the Jail, Tax, and Chance spaces and collect rent on them, various nasty ways to accidentally (and not so accidentally) die, extra railroads and utilities that will allow players to charge obscene amounts of rent, and new ways to extort huge sums of money and favors from friends and family. These ideas never came to fruition.