When my kids were all about that age (I have four and they are two years apart each - stairsteps!) I bought them a bunch of outdoor stuff - because like your son, they had all sorts of electronic gadgets and I wanted to get them outside into the fresh air. I bought them pogo sticks, hoola hoops, bikes, a badmitton set, a basketball goal and ball, baseball bats, gloves, etc.
Oh, and a scooter - one of the old school kinds. And a skateboard - which started a huge interest in that with my boys, who were 6 and 8 at the time.
We lived in a neighborhood so they had lots of friends as well. That's an important part in all the outdoor stuff.
Oh, I also got them some kits to collect bugs, a telescope, that sort of scientific thing.Most of these were a HUGE hit - and believe it or not, one of their favorite things was that ridiculous pogo stick.
Oh, and I also recommend books - maybe a set of books like the Narnia series, or JRR Tolkein, or maybe Ray Bradberry or the Harry Potter books.