There were video games.
You could buy PONG as it's own machine for your tv.
You could also get Magnovox's Odyssey system (later replaced by Odyssey 2 in the 80s) or late in the 70s, Atari's VCS system.
Kids also had those handheld games (like Football) that used LEDs.
Oh, I know, but not until the late 70's, as I remember. And they were pretty rare.
We had that Pong machine, before we got an Atari. My uncle still has that Pong thing, and it still works.
But we STILL preferred to play outside.