In Little Shop of Horrors, much ado is made about the fact that Audrey and Seymour are getting married tomorrow. There's even a Cut Song called "We'll have tomorrow". They're both dead by the end of the day.
The Screen-to-Stage Adaptation of The Producers has a song about it being bad luck to say "good luck" on opening night. Therefore, everyone wishes Franz to "break a leg" as he dashes off to the show. It's just his luck that a moment later he literally breaks his leg.
In Julius Caesar, when the Ides of March, previously established as a day of danger for Caesar, arrives, Caesar happens to pass by the soothsayer that predicted that danger would befall Caesar on that day... and proceeds to boast that nothing has happened to him... yet.
In the Lillian Hellman version of Candide, after the auto-da-fé is over and Pangloss and the heretics have been executed, the Inquisitors announce to the people of Lisbon that they have been saved from the threat of an earthquake. The earthquake happens immediately after the Very, Very Old Inquisitor says, "The danger is over."
The play Auntie Mame has a prologue in which Edwin Dennis (in voiceover) dictates his will, directing that, in the event of his death, Patrick, his only son and sole heir, be placed in the care of Mame Dennis, "that crazy sister of mine." The music becomes facetious as he adds, "Since I keep myself in splendid physical condition through daily workouts at the Chicago Athletic Club, I am confident that these provisions will not go into force or effect for many years." The music then suddenly becomes ominous, and the will is followed by a newspaper headline from the very next day: "BUSINESSMAN DROPS DEAD IN STEAMROOM OF CHICAGO ATHLETIC CLUB."