I pulled a lot of these suggestions from an article on lifehack.com, and added a few of my own. If you're trying to entertain children between their homework assignments, maybe some of these suggestions will come in handy.

• Paper airplanes: There's nothing like folding a piece of paper into a dartlike shape and tossing it, watching it arc through the air, and glide to a stop. Or, folding it just a little bit wrong and having it thump like a rock straight onto the floor. I suggest making several and seeing which one flies farthest. I'm competitive like that, though.
• Write a story: This one is a personal favorite of mine, obviously, but I suggest putting together a list of 10 random words and everyone participating picks five and writes a short story. You could also do this with writing poems. Hint: They don't have to rhyme.
• Perform a play: You don't even need a script. Favorite stuffed animals or other toys can stand as actors, family pets can join in. Sky's the limit. If you want to get really elaborate, you can make costumes, write the script, build sets, sing songs...
• Draw maps: So, to draw a map of your neighborhood, routes to school, the planet Earth, an imaginary place, all you really need is a drawing tool and a surface for writing.
• Make a sundial: Do you have a clock, a compass, pebbles or some kind of marker like that, and a stick? On a sunny day, you can build a sundial. Push the stick into the ground, angled north (use the compass). Use the markers to mark where the stick's shadow falls at the passing of each hour. You can then tell time. Get as fancy or as simple as you want with this.
• Juggle: I've never been very good at this one myself, but if you have a few beanbags or oranges or other items that are more or less the same size and weight, now's a good time to learn to pass them from hand to hand.
• Read: If your to-be-read pile looks anything like mine, you officially have my permission to park yourself and enjoy those books.
• Play some board games: If you have board games, this is a great time to play them.
• Sock puppets: You don't need a lot of craft supplies for this one -- just your hand, a sock, and a silly voice. Myself, I used to make sock puppets and have them repeat terms and concepts from my textbooks while I was studying in college, and it sounds ridiculous but it was really helpful. Might be helpful for anyone else in your house who's studying right now.
• Music lessons: Do you have a musical instrument in your house? Depending on what it is and how good you are with it, now's the time to either hide it away forever (I'm looking at you, harmonica I never learned to play properly) or pull it out and practice.
• Birdwatching: If you have a guide to birds and a pair of binoculars (and those are optional), you're set. Bonus: If you have indoor cats, they're probably already alerting you to when there's a bird nearby.
• Draw a family tree: This can easily serve as a way to tell stories you might not have thought to tell your children about their ancestors.
• Go outside and play: Practice social distancing and grab your favorite athletic gear, whether that's a soccer ball or a jump rope, or a stick of chalk for hopscotch.
• Tie-dye clothing: Here's where we get a little messier. If you have clothing dye, freshly washed and dried cotton fabric or clothing, rubber gloves, a large bowl or bucket, and elastic bands or string, you can tie-dye. Use the elastic bands or string to fold, knot and tie the fabric. The tighter, the better. This is how the dye is exposed, or not, to the fabric. Follow manufacturer's instructions on the dye, then remove the item and let dry for 24 hours, then wash. Groovy.
• Start some seeds: For this, you'll need seeds, growing medium, a container for the medium (anything from eggshells to folded newspaper to peat pots from gardening magazines will do), and a sunny spot indoors where the seedlings won't be disturbed. Keep the soil moist but not wet, and once the seeds have sprouted, follow the seed packet's directions on how to plant them outside.
• Papier-mache: A classic. Pick a project: volcano, bowl, free-form sculpture. Build up a form with some paper and tape, squishing it into the shape you want. Tear some newspaper (or other paper) into strips, wet it with watered-down starch, wallpaper paste, or what have you, slick it on in a few layers, then top it with a layer of strips torn from plain white paper to make painting easier. Once dry, cover with tempera paints or acrylics. And if you have built that volcano, remember, equal parts white vinegar and baking soda make for a pretty decent show.
• Painting: If you already have paint and paper, or a canvas, or a board, or a sheet of cardboard even, put down a tarp and go to town.
• Chalk drawings: If you have some pavement and some chalk, this is a fun one. A chalkboard works too.