I sometimes can’t sleep due to stress or sickness. So I have a book on my nightstand for this situation.
It is a field guide to trees in my area. It is very boring and I’m not retaining much of what I read at 3:30 a.m. The point is to sit in a chair and look at trees until I feel I can fall asleep again.
I keep a copy of my automobile insurance policy near my bedside for this purpose. The success rate is 100%, since I’ll awake in the morning still holding the policy halfway through.