My four children and now my grandson have grown up watching me craft.  Thousands of times I have heard the phrase, "Let me do it too".  As a jewelry maker I know the joy of stringing beads to create something stunning and wearable.  Most of the beads I use are just too small for little hands, but... DADA.. wood beads are perfect for children.
A bit of cord and a box of wood beads and most children will create for hours.  I keep a plastic tote filled with all the large hole wood and plastic beads, a pair of safety sissors and some cord.  My 13 year old daughter and 5 year old grandson enjoy creating their own necklaces and bracelets for gifts.  It's a good way to begin teaching color values and shape design.  When the children are very young I let the just string and then I tie the cord.  As they grow older I show them how to alternate the size, shape and colors of the beads for a design.  Old designer boards are perfect for children, especially once they get the magic markers to them and decorate them for personal use.
If you find stringing difficult, dip your cord or elastic in a bit of candle wax and let it dry.  This stiffens the cord/elastic and makes it easier to string.  This will be cut off when the jewelry is finished.
Using a double slip knot will allow jewelry to be adjustable so it's more fun and a bit more fancy.
There are also a lot of larger clasps that children can tie onto the cord to finish their creations as well.
Children love to learn and share their creations with others.  This holiday give them the opportunity to share their joy of life by making jewelry for family and friends.