Story Ideas...

Out of Order

Make a story that is out of order, like one chapter may be the second to the end chapter, but then the next is the start or middle. But the chapters are a bit similar, that no one would suspect they are that out of order except for hints within the chapters.

A way you could do this is events from one person's life. Like they went camping, vacation, and school. But add in subtle hints that has the reader know somethings not right. And that they need to figure out the correct order.

Like that they have a boy/girlfriend in one chapter. But in another chapter say that they love being single although they've never dated anyone before

Or bring up an event that the person has done, but it will be a future chapter. And of course you can make the hints as subtle as possible. So it's an amazing mystery of how the order is supposed to be.