If it isn't naturally fun for your kids, though, it's time to change their thinking. While not every child will want to be a writer, being able to write fiction is an important skill. For one thing, good writers are better readers. You have to understand the structure of a story, the art of characterization, plotting and a host of other literary skills to be able to write a story. When you've struggled with those in your own stories, you will appreciate them in others.
Writers understand what makes a good story.
At the very least, children need outlets for their vivid imaginations. Story writing should start as soon as the child can talking complete sentences. Let them tell you the story into a tape recorder, and later let them dictate stories to you. Don't worry about fact or fiction, just write what they say. Let them start by telling you about their day, or their vacation.