Sacred Haven of Debauchery

As far as I understand, if an event isn't tied to a holiday or season (like Valentine's Day or summer), it reruns once, after a year, and then you'll never see it again. I haven't quite figured out how seasonal and holiday events work yet, but I can assume that the logic is roughly the same, with the caveat that instead of rerunning an old event, a new one will simply be introduced.