I can relate to you, always looking for activities that are both fun and productive to keep her busy. Every evening I spend time and let speak her mind, her thoughts about school or whatever goes in her mind. She has never ending "Why?" :)

Few things she had liked so far -

  World/Asia/Country specific maps arranged as puzzles.
  Legos/Block games.
  Coloring books.
  Cycling.

Starting scratch this weekend - https://scratch.mit.edu/