If you have event registrations or event attendances logged in your account you can segment down on those events. To segment on events go to Audience > Search.
Then chose Activity > Event. You can then select either "Has Registered" for event registrations or "Has Attended" for event attendance criteria.
To drill down on event registrations, click "Has Registered." You can then choose from any of the following criteria: Event Name, Event Date, Ticket Type, Event Discount Code, Datetime, or Organization.
To drill down on event attendances, click "Has Attended." You can then choose from any of the following criteria: Event Name, Event Attendance Type, Datetime, Organization, Collector, Attendance Host Name, or Has Hosted an Event.
After you've made your event registration or event attendance selections, click "Save Selections" and proceed with editing your segment.