Have you read Holes (seeing the movie is fine too, as it's like the one movie that was 99.9% faithful to the book that I've ever seen).
The climax relies on understand three-four-five-six-seven (the one story is seen is mentioned as it's a passing event in another which only works by not knowing who you're reading about until it's conclusion, but the sixth and seventh ones I think are movie exclusive... it's been a while since I read the book, but the movie was doing flashbacks to begin with so why not. Another story is a flashback to the character hearing the story that we then flashback to... Basically, there are three real stories that are all true to some extent in the fictional setting and a lot of jumping around in to each of them) stories that all contribute to the final action and all take place.
To help break this up, all time periods are described in the book in seperate chapters (again, one is recalled by recalling hearing the story at an earlier point in time, but they make it clear). And are told in quasi-tandem (aside from the modern setting, no time period is featured back to back).
Basically, the storyies told are as follows:
- A story about a boy in a juvinile detention camp in the Texas Desert that really establishes critical elements of the camp and shows that it's harsh enough that the kid provokes a rattle snake into biting him just to get out of that camp.
- The present story about the main character, the boy who replaces the vacancy left in the camp in story 1.
- A flashback that shows the events leading up to the boy's arrest, conviction, and sentancing that resulted in him going to the camp. This also sets up the main character's father (his grandfather in the film) relating the story in the next segment.
- The story of the main character's great-great grandfather, and the supposed origin for the family's rotten luck in the form of a gypse curse placed on the man.
- The story of a Texas School House teacher in what is presumably post-Civil War 1800s and her tragic love for an African-American man who would do handywork around the school so they could be closer to each other (This is the only story to my recollection that is told over multiple chapters, as it's seemingly disconnected nature seems at odds with the book. It's also notable as it is the main character is not aware of the entire story only his connections to it).
- Various other flashbacks that may or may not have been in the book in such a way that helped to bridge all the connections. Several flashback scenes were included that in the book were communicated via dialog only and none actually changed the point, just visualized it.
So again, if you haven't read the book, its a great use of the Flashbacks and again, the one change between the book and the film was that the main character in the book is described as being overweight and later having noticably slimmed down as a result of his physical activites in the book... which is not a word used to describe the teenage Shia LeBouf who played the main character in the film (Shia LeBouf was commited to trying to put on the weight, but the books author personally stepped in and said it wasn't needed in the movie and even threated to rewrite the book so the character was slim to begin with in all iterations if LeBouf was going to continue to try and put on excess weight and then lose it fast during a point where his body was still changing and was likely to have some serious health complications). In the course of the story, this amounted to dropping about two or three lines and giving the character's nickname of Caveman a different origin story (in book, it was in part because of the character's size. In the film, it was because he found a fossil, which also happened to be an event in the book.).