Children are usually fascinated by sewing. The needle goes in and out, and then two things are stuck together. Here are some simple projects that a child can easily do, and they will learn a valuable life skill for later without realizing they are learning.
Small children can start sewing with lace up cards.
Cut it out and punch some holes around the edge with a hole punch. A shoelace becomes a 'needle' and thread. This becomes a wonderful rainy day project especially if you can find some multicolored shoelaces. When your child has progressed from lace up cards, have them sew on buttons. Buttons are simple because the holes are prepunched and can be so much fun.