Gaming system, a method of gaming and an additional game controller

1. A method of gaming for use with a gaming system having a plurality of gaming machines, each of the gaming machines being configured to play a base game, each gaming machine having a) a credit input device operable to receive a physical item representing a monetary value to establish a credit balance, the credit balance being increasable and decreasable, b) a game controller comprising a processor and memory, the memory storing instructions, which, when executed, cause the game controller to at least play the base game, and c) a display device, the gaming system further having an additional game controller executing the instructions which causes the additional game controller to play an additional game with respect to a plurality of jackpot prizes, the additional game controller having a communication interface configured to be in communication with each of the plurality of gaming machines, the method comprising:

generating a trigger by a first gaming machine of the plurality of gaming machines;

receiving at the additional game controller the trigger from the first gaming machine;

selecting, by the additional game controller in response to receiving the trigger a first jackpot prize from the plurality of jackpot prizes in the additional game;

displaying on the display device the first jackpot prize selected in the additional game;

selecting, by the additional game controller, a subset of the plurality of gaming machines to participate in the additional game together with the first gaming machine;

determining, by the additional game controller, a game outcome of the additional game that wins the first jackpot prize selected;

selecting, by the additional game controller one of the plurality of gaming machines to participate in the additional game to display the game outcome determined to win the first jackpot prize selected;

initiating, by the additional game controller, the additional game for play by the gaming machines participating in the additional game;

displaying the game outcome of the additional game determined at least at one of the plurality of gaming machines participating in the additional game; and

controlling the display device to display an increase of the credit balance of at least at one of the plurality of gaming machines participating in the additional game with the first jackpot prize selected.

2. The method as claimed in claim 1 , wherein selecting a subset of the plurality of gaming machines to participate in the additional game includes randomly selecting in respect of all of the gaming machines.

3. The method as claimed in claim 1 , and further comprising the first gaming machine generating the trigger in response to a trigger event occurring on the first gaming machine.

4. The method as claimed in claim 1 , wherein selecting a subset of the plurality of gaming machines to participate in the additional game includes selecting based on which gaming machines have been active in a designated period.

5. The method as claimed in claim 1 , wherein selecting a subset of the plurality of gaming machines to participate in the additional game includes selecting based on whether a designated wager has been made.

6. The method as claimed in claim 1 , wherein selecting a subset of the plurality of gaming machines to participate in the additional game includes deeming each of a plurality of designated gaming machines to participate in the additional game.

7. The method as claimed in claim 1 , further comprising conducting separate additional games for each gaming machine which is determined to participate.

8. The method as claimed in claim 1 , further comprising conducting a single additional game for all of the gaming machines which are determined to participate.

9. The method as claimed in claim 1 , wherein selecting one of the gaming machines to participate in the additional game to display the determined game outcome determined to win the first jackpot prize selected includes assigning via the additional game controller a higher probability of winning the first jackpot prize selected to the first gaming machine with respect to the gaming machines determined to participate in the additional game.

10. The method as claimed in claim 1 , wherein selecting one of the gaming machines to participate in the additional game to display the game outcome determined to win the first jackpot prize selected includes randomly selecting the one of the plurality of gaming machines to participate in the additional game.

11. A gaming system comprising:

a plurality of gaming machines, each gaming machine operable for independent play of a base game, and having a) a credit input device operable to receive a physical item representing a monetary value to establish a credit balance, the credit balance being increasable and decreasable, b) a game controller comprising a processor and memory, the memory storing instructions, which, when executed, cause the game controller to play at least the base game, and c) a display device operable to display a jackpot prize winnable in an additional game; and

an additional game controller in data communication with the plurality of gaming machines, executing the instructions which cause the additional game controller to at least:

receive a trigger from a first gaming machine of the plurality of gaming machines, determine in response to receiving the trigger which of the plurality of gaming machines are eligible for the additional game,

select in response to receiving the trigger a first jackpot prize from a plurality of jackpot prizes winnable in the additional game,

cause the display device to display the first jackpot prize selected in the additional game, select a plurality of second gaming machines of the plurality of gaming machines to participate in the additional game together with the first gaming machine,

determine a game outcome of the additional game that wins the first jackpot prize selected,

select one of the gaming machines to participate in the additional game to display the game outcome of the additional game determined to win the first jackpot prize selected,

initiate the additional game for play by the plurality of gaming machines participating in the additional game,

display the determined game outcome at least at one of the plurality of gaming machines participating in the additional game, and

control the display device to display an increase of the credit balance of at least at one of the plurality of gaming machines participating in the additional game with the first jackpot prize selected.

12. The gaming system as claimed in claim 11 , wherein executing the instructions further causes the additional game controller to select randomly in respect of all of the gaming machines.

13. The gaming system as claimed in claim 11 , wherein the first gaming machine generates the trigger in response to a trigger event occurring on the first gaming machine.

14. The gaming system as claimed in claim 11 , wherein executing the instructions further causes the additional game controller to select based on which gaming machines have been active in a designated period.

15. The gaming system as claimed in claim 11 , wherein executing the instructions further causes the additional game controller to select based on whether a designated wager has been made.

16. The gaming system as claimed in claim 11 , wherein executing the instructions further causes the additional game controller to deem each of a plurality of designated gaming machines to participate in the additional game.

17. The gaming system as claimed in claim 11 , wherein executing the instructions further causes the additional game controller to conduct separate additional games for each gaming machine which is determined to participate.

18. The gaming system as claimed in claim 11 , wherein executing the instructions further causes the additional game controller to conduct a single additional game for all of the gaming machines which are determined to participate.

19. The gaming system as claimed in claim 11 , wherein executing the instructions further causes the additional game controller to assign a higher probability of winning the first jackpot prize selected to the first gaming machine with respect to the gaming machines determined to participate in the additional game.

20. The gaming system as claimed in claim 11 , wherein executing the instructions further causes the additional game controller to select randomly the one of the plurality of gaming machines to participate in the additional game.