On the last day of worms we made a worm farm. Everyone had a job alternating sand, dirt, mud, and food (egg shells, lettuce, banana peel, etc) and squirting water after each layer to keep it n ice and moist. Then we dumped the worms on top and sprayed them. We got to watch the worms burrow down in to the worm farm. It was so cool to watch them dig their tunnels.
After the kids left I covered it with black paper on the sides and top so the worms thought it was night. The next day we could see the worms up against the jar and their tunnels and the layers mixing.