You work to strengthen unions and take down capitalism.

Well, if the plan is to eventually continue to sleep, I'd say nothing. Once you get up and start doing something you will just get more awake and it will taken even longer to fall back asleep.

Jack it, then you can sleep again

Read a book!

Yin yoga is good for this exact situation. I do it without getting out of bed usually (husband is a heavy sleeper). I read somewhere "vigilance is the enemy of sleep" and that makes sense. Yin yoga is designed to calm your nervous system and I find it does help knock me back out. Try to let go of unhelpful thoughts, if you think you need to remember something for the morning place a rubberband around your wrist to make you notice and remember in the morning then let it go.

If it's so late (early?) that you might as well get up, a morning run, jog, or walk as the sun is rising is a very encouraging activity. It feels so happy to see the new day born, and vigorous exercise in particular (so if you can run instead of walk, do it) is invigorating.

I shitpost on this obscure Internet technology forum called Lemonworld or something to market my movies and confuse some tech nerds.

It's an incredibly productive use of my free time.

I did cognitive behavioral therapy for insomnia years ago, and at the time had the same issue with waking up and then laying in bed for hours trying to get back to sleep. It led to a horrible cycle of anxiety about whether I'd be able to sleep, which of course made it harder to sleep. The most important rules are to try to go to bed and get up at the same time every day. If you're awake in the middle of the night and can't fall back asleep after ten minutes, get out of bed and do something quiet with no screens. I recommend hand washing dishes, dusting, or folding laundry. This is productive, calm and quiet, and boring enough that you will be happy to go back to bed when your body says you're ready. When you start doing this, you're going to be even more tired during the day. Just suffer through it, don't take a nap and don't try to counteract it with caffeine or other stimulants! That will only exacerbate the cycle of insomnia. I also recommend keeping a journal of when you go to bed, every time you wake up, and when you're finally up for the day. You might find that you naturally wake up less if you give yourself a different bed time window.

Smoke a joint and go back to sleep.

Practice your telekinesis and telepathy

I will eat a couple melatonin gummies and then read until I get sleepy enough to turn out the lights.

Listen to an audiobook.

I started listening to Alan Watts while I find the topics really cool, his voice just puts me to sleep.

Do laundry?

Watching tool restoration videos used to cut my insomnia significantly, usually after one half an hour video I'd have a hard time keeping my eyes open.

Truth is I stopped having insomnia when I left the call center and turned my life around, so the real advice here is get help because it's most likely a psychological thing

Mindfulness practice, set the intention to consciously watch everything your mind is doing.

This kind of practice may also help with getting back to sleep.

Try to stay awake. Sounds counterintuitive but forcing yourself to sleep is stressful by itself. Getting it of your mind can help.

I had this happen to me this morning!

Was up at 4am and thought.... oh! I can scan some of those old family photos I've been meaning to get to. Just ended up on my iPad reading the news and browsing Etsy and eBay for two hours instead. Every time, I remind myself I need to keep screens out of the bedroom.

Otherwise, if it's nearly morning anyway, I find it a good time to listen to music and make playlists. If it's too early, I'll read a book.

Eat melatonin

Instant ramen.

Put your running shoes to work.

Save up a stash of Interesting audiobooks, podcasts for times you're feeling like it'll take an hour or more. (Not -too-interesting.) Boring ones once you feel like keeping your eyes closed.

I usually stay in bed and think about my next DIY-project and how exactly I want to do it. Or read something that is interesting but not to exciting.

Watch restoration videos without commentary on YouTube and you'll be back to sleep in no time. Always work for me.