Here are some examples to illustrate:
* In *The Hunger Games*: The initiating incident is Katniss volunteering as tribute to save her sister. This single act throws her into the perilous arena and sets the entire plot in motion.
* In *Harry Potter and the Sorcerer's Stone*: The initiating incident is the arrival of Hagrid and the revelation that Harry is a wizard. This event upends his mundane life and sends him to Hogwarts, where the rest of the story unfolds.
* In *Pride and Prejudice*: The arrival of the wealthy Bingley and the arrogant Darcy in the neighborhood could be considered the initiating incident. This event introduces the primary conflict and sets the stage for Elizabeth and Darcy's relationship to develop. However, a more precise initiating incident might be the initial Netherfield ball, where Elizabeth makes her first impression of Darcy and he hers.
The initiating incident isn't just any random event; it's carefully chosen to create a compelling narrative. It should raise stakes, present a clear conflict, and motivate the protagonist to take action.