1. An auction-based game system comprising: a computer, connected to at least one network and operating predetermined software, for: (i) selecting a plurality of users for participating in an auction-based game, each user having a telephone with a unique telephone number, and wherein each telephone number has the same number of digits; (ii) inviting bids from the selected users to determine a first digit of a set of numbers; (iii) receiving bid data from said selected users, transmitted over the at least one network, for determining the first digit in the set of numbers; then (iv) inviting bid data from a plurality of said selected users on an additional digit for the set of numbers, and receiving bid data from said users for determining said additional digit; (v) continuing to invite bid data from a plurality of selected users, and receiving additional bid data, until the number of digits determined reaches the number of digits in the telephone numbers of the selected users; (vi) selecting a winner of the auction-based game using the predetermined software implementing predetermined rules and the winning number, and (vii) generating and outputting an audio and/or visual winner-notification message to each of the telephone devices to notify at least one of the users of the winner of the auction-based game.