Box of crayons and a coloring book is always great. Also bubble bath with their favorite cartoon on it and a spongee. Those are the two gifts I give out pretty often if i dont know the child that well.
What is she/he interested in? Can you ask the parents to see if they have any suggestions on what the child may want/need. Otherwise I would go with the classic coloring books, etc. Kids that age can't resist coloring.