A fifth week event is a novelty comic book promotion. Comic publishers schedule releases in four-week cycles, releasing on a particular day of the week (e.g., every Wednesday). On an occasion that a month has more than four weeks (i.e., a fifth Wednesday), publishers often sell unusual comics to fill in the scheduling gap. The fifth week event has been discontinued since longer crossovers, such as Blackest Night, run for months at a time, requiring more tie-ins and fewer simultaneous crossovers.