My kids, like most other young children, are happy when they are wet. Water draws them like no other activity.
We put a tub of water with a squirt of baby soap on the front porch. I added some baby dolls and a few cups for pouring, and we had an instant baby bathtub.
Nora always drinks the bathwater, even when it isn't her own. She will reach into the tub when SuperSam is bathing and try to get water to drink. When she and Lucy bathe together, she drinks the water the whole time and sucks it out of the wet washcloths floating around her. I've almost given up trying to prevent this, despite the implications. (Two toddlers in a bathtub means there is almost a 100 percent chance that she is drinking pee, right?)
Since there were only imaginary babies (and therefore imaginary pee) in the bath this time, I didn't even bother asking her not to drink the water.
It's tough to find an activity that can peacefully involve and occupy all three of my children at this stage. This one worked nicely for everyone. I'm planning to try this indoors with the girls one morning while SuperSam is working on some of his projects. So far, the most challenging thing about homeschooling is finding things to keep The Sisters occupied during "school time."