A method of operating a wagering game comprises receiving a primary wager, displaying a randomly selected outcome of a primary wagering game, and displaying at least one progressive jackpot. A first portion of the primary wager is allocated to fund the at least one progressive jackpot. An increment amount to be added to the at least one progressive jackpot is randomly determined, the at least one progressive jackpot is incremented by the increment amount, and in response to a triggering event, the at least one progressive jackpot is awarded. Alternatively, a random determination is made whether to increase the at least one progressive jackpot by a predetermined increment amount and, in response to a determination to increase the at least one progressive jackpot, the at least one progressive jackpot is incremented by the predetermined increment amount.