My favorite modern Events Snowball story is The Warrior’s Apprentice by Lois McMaster Bujold. I was going to link to the copy in the Baen Free Library, but that library has been gutted of most of its holdings due to agreements with other vendors, alas. So I will pick an example from a roleplaying game: the warrior Ichiro Chikara is sent by her small border clan to run hundreds of miles to the capital to request re-enforcements against a possible invasion. She is sent not because of political connection nor skill in court etiquette, but because she can run fast. Just before she reaches the capital, she helps rescue two girls and their bodyguard from bandits. The girls are the key to immediately seeing the Empress in order to deliver her message, instead of waiting weeks for an audience. She becomes entangled in a prophecy. The Empress, in hopes of making the prophecy come out well, sends Chikara and the others out with the re-enforcements. But on the way, they encounter … The story grows like a snowball rolling downhill.

The same roleplaying game is also a Man Learns Better story. Akechi Renju, a young warrior hoping to become a great commander, is given the unimpressive duty of escorting two girls to the capital hundreds of miles away. He expect that he will lead a small patrol to protect those girls, but instead a powerful wizard magically transports the three of them to just outside the capital. But in the single mile they have to walk to complete their journey, they are attacked by bandits. Fellow travelers rescue them, Next, the older girl reveals their mission: they are to see the Empress herself. Renju is not ready for that level of court etiquette! Then he learns that they are the subjects of a prophecy. Surely, the kami spirits hate him, to send him so far from the expected path of his life. He does get to command a small patrol, but it is made out of the unruly fellow travelers who rescued them and the two uncanny wizard girls.