This question – what’s on the box? – used to be heard frequently in the homes of Britain. This was because televisions used to be box-shaped and because there was no internet so watching TV together was the national pastime.
This phrase is becoming obsolete, not least because TVs are now flat. But more significantly because nowadays, people rarely watch broadcast TV. They tend instead to watch catch-up TV (e.g., via BBC’s iPlayer) or streaming services (such as Netflix) more often than not, alone.
As I say,
“If you wanna pacify your kids, turn on the box and they’ll shut their gobs.”
Groucho Marx once said,
“I find television very educating. Every time somebody turns on the set, I go into the other room and read a book.”