Read. Study. Listen to music or radio shows (podcasts). Play music. Board games. Prep food for the next day (pizza dough ought to rest at least overnight, for instance). Tidy and clean so you don't have to do that while the sun's up.

Generally, get tired and go to sleep much earlier because you're not hyper-stimulated late into the night by glowing rectangles.

The 90s? That can't be the dark ages already :) How about listening the radio, podcast, music? I wonder what the effects of audio are on sleep.

We watched TV in the 90s. Lots and lots. Try the 40s.