It could be about a boy who is profoundly in love with pizza. So in love, and loyal to pizza, that he decides to take over every pizza business in the world! MWAHAHAHA!!
or
It could be about a guy that has to write a story for an English project, and as he tries to figure out what he wants to write about, he faces difficult choices of ideas. Then, events in life happen that leads to the protagonist choosing the chosen idea. (Wow...that was kind of confusing)
or
it could be about a four years old girl who decides to sail around the world. On her journey, she learns life lessons. In the end, it turned out to be all a dream, but the point is, you teach the readers something meaningful. (example of something meaningful: Never lie, Don't kill people for it won't solve anything, etc.)
or it could be some romantic story between a person and the person of his/her dream. They both can only meet with one another in the protagonist's dream. In the end, the dream character leaves. Sad love...
Hope this helps. I enjoy giving out ideas. I am glad that I could share my ideas on this type of things.