Gaming machines and systems are configured to present viral gaming events. Once a viral gaming event is triggered, it is presented at one or more first gaming machines at a first time. The viral gaming events spreads to other gaming machines, such as one or more second gaming machines where it is presented at a later time. The viral gaming event may continue to spread to numerous gaming machines. The viral gaming event may comprise a game or a bonus or secondary event, such as a bonus award event to a base wagering game presented by the gaming machine. Feedback or metrics may be used to control the machines to which the viral gaming event spreads and/or the rate of spread.