Four years ago we added Santa's Socks to our Discovery Center. I remember searching everywhere for colorful socks for this activity. Now you can easily do this at home because Christmas socks are not only everywhere but cheap (preschool teachers like things that are cheap or free). Check out your local store where things are a dollar. Fill a basket and add clothespins. More info and the 'how to':
http://metamoracommunityprek.blogspot.com/2016/12/santas-socks.html
