Patent ID: 8550904

Claim:
A wagering game system comprising: a game controller; a physical memory operatively coupled to the game controller; and a wagering game machine, comprising a display device, communicatively coupled to the game controller, wherein the game controller is operatively configured to perform acts comprising: determining a mystery threshold trigger level for an n-th unit prize and setting a threshold trigger level counter to an initial value; discretizing an input wager into a plurality of discrete eligibility units; adding the plurality of discrete eligibility units to a discrete eligibility units counter for the wagering game machine; subtracting periodically a discrete eligibility unit from the discrete eligibility units counter and correspondingly incrementing the threshold trigger level counter; determining whether the discrete eligibility unit used to increment the threshold trigger level counter triggers the n-th unit prize; triggering the n-th unit prize if the threshold trigger level counter meets or exceeds the threshold trigger level or if the threshold trigger level counter meets or exceeds another predetermined value relative to the threshold trigger level; and awarding the n-th unit prize responsive to the act of triggering or, absent such triggering, iteratively performing at least the acts of subtracting and determining until no discrete eligibility units remain in the discrete eligibility units counter.