A couple more things:
Like Artana, we do museums, zoos, & other things on weekends. Those things will influence the choice of books to read. I pick some of his books to guide him.
GS10 is in the 5th grade and rarely has homework to bring home. I guess he does it while he's waiting on other kids to finish class work. I think it's great that he is motivated to do that, but he's not getting a habit of studying outside the classroom. He's also not self-motivated to dig deeper in maths & science, which I'd like him to do.