Another good thing about the competition is that it is open to people of all ages, children and teenagers included.
If you're looking for something to do with the kids this summer, it seems like this would make a great family project. You might even start by introducing them to Star Writers, by Sister Amatullah Al-Marwani. Star Writers is a wonderful workbook for Muslim children that introduces them to the world of writing creative stories with Islamic themes. Although it is for children, I, too, am benefiting from the book and learning how to write more creatively.
In any case, check out the guidelines for the The Islamic Foundation Writing Contest.