This is the answer 'Solar System'. Write 5 questions where 'Solar System' is the answer! Sound easy? The first couple of questions might be, but after that you will start to dispute what you have written. This is a great collaborative group activity where you will be sure of plenty of discussion and argument especially if the students start thinking about other answers for the question. This is actually an example of a 'closed answer...there is only one answer; but to create the question to get to that answer takes a lot of thinking and synthesising.
Graphic organizers such as Kidspiration or Inspiration or online versions such as bubbl.us or Webspiration are useful.