When I did ECC I also had a 5 yo and a 2 yo. I tried to include the little ones in the crafts and cooking when possible and also found some library videos on the countries, biomes, cultures we were studying and they would watch them with the bigger kids.
One hint that seems to work for a lot of families is to give one-on-one attention (maybe that means "play school") with the little people first and then move on to your real students!
Also, find lots of activities that can be done with minimal supervision. My little ones didn't like playing far away from me, but they didn't mind being in the next room over with play-doh, paint, kiddie scissors, glue, paper. They liked "washing dishes" where I'd give them a big plastic container of soapy water, and some unbreakable things (a baby spoon, a set of measuring spoons, etc.) and a dishcloth and let them at it. Another fun activity is an indoor sandbox. Fill a large lidded plastic container with either cornmeal or grits (uncooked, of course) and add in a few Matchbox cars (especially the digging kind like bulldozers and dumptrucks) and there's an instant indoor sandbox. If you have a winter day, you can bring in a bucket of snow and get out some scoops and spoons.
The common theme, I'm afraid, is mess. That comes with the territory.
Another helpful thing is to train the older kids to do a lot of what you already do, whether it's laundry, straightening a room, basic cooking, etc. I rely on my bigger kids to handle a lot of the mess.
A great hint a friend gave me was to make sure you assign times for the bigger kids to play with the little ones. So, maybe for 15 minutes, you can tell Sally to play with Suzy and Sammy while you do math with Bubba. The big kids enjoy this responsibility and the little ones like the attention. Of course, you have to consider the family dynamics! You can simply make this "playtime" or you can assign what to do ("read a picture book" or "can you make something with blocks...")
If you have a particular show or video that your child likes, you can build that into the day and you'll have a half hour that you can devote to the bigger kids. You can either record the show or use something like Tivo so that you can have your little ones watch it at a good time.
Oh, God's not surprised by the chaos that little kids create and he knows that it can interrupt school, and He's still blessing your little homeschool...
Kelly, wife to Jim since 1988, mom to Jamie (a girl, 1994), Mary (1996), Brian (1998) and Stephanie (2001).