GAMING MACHINE, LINKED GAMING SYSTEM AND METHOD WITH VARIABLE ELIGIBILITY FOR AN AWARD

1 . A method of awarding an award on a gaming machine, the method comprising:

a) in a random selection process selecting an eligibility criterion or eligibility criteria from a plurality of possible eligibility criteria, whereby the selected criterion or criteria is deemed an active award trigger event;

b) monitoring game play activity on the gaming machine for occurrence of the active award trigger event;

c) when the active award trigger event occurs as a result of game play activity on the gaming machine, awarding the award; and

d) following the completion of step c), or following the occurrence of another event:

i) deeming the selected eligibility criterion or criteria an inactive award trigger event; and

ii) repeating steps a) to c).

2 . The method of claim 1 implemented on a gaming machine that forms one of a plurality of linked gaming machines, the method further comprising:

communicating the active award trigger event to the linked gaming machines;

monitoring each of the gaming machines for occurrence of the active award trigger event;

performing process c) only for the first of the gaming machines to achieve the active award trigger event; and

performing process d) following the award of the award by any of the gaming machines.

3 . The method of claim 2 further including displaying information reporting the active award trigger event on a display of each of the linked gaming machines.

4 . The method of claim 1 implemented on an individual standalone gaming machine, the method further including displaying information reporting the active award trigger event on a display of the gaming machine.

5 - 6 . (canceled)

7 . The method of claim 1 wherein either one of or both sub-steps i) and ii) are performed substantially immediately following the award of the award.

8 . The method of claim 1 wherein the method comprises delaying the performance of sub-step ii) following the award of the award.

9 . (canceled)

10 . The method of claim 1 wherein the plurality of possible eligibility criteria varies over time, wherein the variation is either:

in a predetermined pattern; or

includes at least a component that is random.

11 . (canceled)

12 . The method of claim 1 wherein the award is a feature game that operates over a plurality of game events.

13 . The method of claim 1 wherein the award is a special prize selected from the group comprising a progressive prize, a non-cash prize and a large prize.

14 . The method of claim 1 wherein the award remains the same for all selections of active award trigger events.

15 . The method of claim 1 wherein the award differs over time.

16 . The method of claim 1 wherein one criterion or all or substantially all of the possible eligibility criteria comprise the occurrence of a certain symbol or combination of symbols, wherein at least one of the symbols must occur and the manner in which the symbols must occur is different between different possible eligibility criteria.

17 . The method of claim 1 wherein one or more of the possible eligibility criteria have different probabilities of occurrence.

18 . (canceled)

19 . A gaming machine comprising:

a game controller comprising a computational device and data storage in communication with the computational device; and

a user interface comprising at least one display and one or more input devices in communication with the game controller;

wherein the data storage includes a definition of a plurality of possible eligibility criteria, each defining a circumstance that arises during play of a game on the gaming machine;

wherein the game controller selects, using a random selection process, one or more of the plurality of possible eligibility criteria to thereby define at least one award trigger event, and monitors play of the game on the gaming machine for occurrence of the award trigger event; and

wherein when the award trigger event occurs, the game controller causes the gaming machine to award an award.

20 . The gaming machine of claim 19 wherein following the occurrence of one or more predefined events the game controller again selects, using a random selection process, one or more of the plurality of possible eligibility criteria thereby defining a new award trigger event, so that the at least one award trigger event is variable.

21 . The gaming machine of claim 20 wherein the one or more predefined events may comprise events selected from the group of: the occurrence of the current award trigger event; a time-based event, the occurrence of which is dictated according to either determinative or random criteria; receipt by the game controller of a predefined command; and a combination thereof.

22 . (canceled)

23 . The gaming machine of claim 19 wherein in different selections of one or more of the plurality of possible eligibility criteria to define at least one award trigger event, the selection is made from different sets of possible eligibility criteria.

24 - 25 . (canceled)

26 . The gaming machine of claim 19 wherein the award is a feature game that operates over a plurality of game events.

27 . The gaming machine of claim 19 wherein the award is a special prize selected from the group comprising a progressive prize, a non-cash prize and a large prize.

28 . The gaming machine of claim 19 wherein the award varies for different occurrences of the award trigger event.

29 - 44 . (canceled)