Many five-year-olds, given a pair of compasses, will use it to stab their neighbour.  But the better-behaved ones should be able to manage this:

Draw a circle.  
Centre a point on its circumference, same radius, draw an arc within the circle, running from circumference to circumference.  
Centre a point where this arc meets the circle, same radius, draw another such arc.  
Repeat.  
By magic, after six arcs, you end up where you started.