You can make some simple shapes for the felt board and have them put them up and take them down and arrange the shapes. You can approximate a sandbox by getting a large pan and putting cornmeal in it for them to sift through and make shapes. You can also put shaving cream on a tray and have them draw in it. My daughter loved to take all the Tupperware out of the cupboard and put the lids on things. I knew a teacher who would give young children a loop of sticky tape that they could attach to different things around the room. That would buy enough time for the teacher to talk to the child's parents. Very young children do have a much shorter attention span, so it's hard to find something truly time-consuming, but I hope these ideas help.