Learn to crochet. Make doll blankets or baby blankets.
Make holiday gifts to save until then - great idea.
Make Shutterfly books from old family photos for older relatives.
Upload family vacation photos and set to music.
See if first responders in your area can accept baked goods.
Play board games.
Keep a tally of birds in your backyard.
Check Girl Scout website for activity ideas.
Check miniature calendar website for inspiration and make similar projects.
Give each child a sketchbook to fill.
Learning skills like simple home repair, sewing on buttons, stuff like that - leads to increased self-esteem and confidence.
Order a beginning coin collection or stamp album and look online for youth clubs.
Lots of free time to let their minds wander. It’s good for kids to be bored sometimes.
Learn to type.

Good ideas here. Thank you! I’m not used to being a stay at home mom, so this gives me some ideas to play with.

I have a 9 and 12 year old. They’ve been playing a lot together. And going to back to “old” toys. They’ve completely rediscovered LEGO friends and I bought them some new sets. I also bought lots of craft supplies. We have a neighborhood pool we’ve been going to, and that’s helped. They’ve also been baking, learning tik tok dances (they get them from YouTube), and had a couple play dates. Lots of FaceTime with friends.

If you're not working, more screen time is not the answer! You are in major luck.

Can you come up with a summer family project or two or more?

Random ideas
Build a free little library
Sew masks to donate
Make a detailed map of your neighborhood
Make a family tree and interview family members, starting oldest to youngest. Write it up and bind in a book. Holiday presents for everyone for next year
Bake every recipe on a cookbook and write reviews
Memorize every country in Africa
Learn to play ukelele
Invent a new sport
Volunteer in a food bank garden or warehouse (low contact volunteering)
Call up a local nursing home and see if any residents need buddies to chat with. Many are lonely since families can't visit.
Write to pen pals

Give your kids some random ideas, but the best projects are the ones they come up with themselves.

Playing video games with his friends. Taking walks with me after dinner. Doing IXL to practice math. Watching Netflix. Getting snowballs. On the weekend, we might go hiking somewhere. That’s it. He’s fine with it. He also does his laundry.

I have boys who are 10 and 12.
I have been taking them jogging every morning before it gets hot.
We also play a lot of D&D, and they have been working on their own campaigns (I would rather have cheesecake).

My girls are 11 and 7. We live in downtown DC. They’ve been binging The Simpson’s ,trying various baking projects (today was a simple cheesecake), practicing violin and piano (the younger one loves to practice,for the older one it’s just cursory), walking the dog, family bike rides in the late afternoon or early eve), reading books (have to nudge them to do, but they both enjoy reading), tennis with each other or with us. We’ve had a couple of play dates but they haven’t been very successful (lots of tween girl drama that we’re trying to distance ourselves from but I think we just need to try other friends). We had a couple great days with friends who live near Annapolis — swimming in the south river, splashing through a creek), but I agree we shouldn’t be doing that much. What activities have been hits in your home? I should add that I’m not working full time at the moment so can handle kids more than I’m sure many parents now. Totally understand if your answer is more screen time!