Our project for children for the Feast of Saint Andrew — especially appropriate for the patron of fishermen — is to make a sun catcher of the Christian fish symbol.. (The fish might also simply be colored by children, or used as a pattern to decorate a cake or large cookie to celebrate this feast.) Full size picture to color can be found here.
To make the sun catcher, you will need paper, colored markers, colored pencils or crayons, scissors, cooking oil, paper towel, yarn or ribbon for hanging.
Directions:
1. Print out copies of the fish design on plain white paper (even better, use white card stock).
2. Have the children color the fish with markers or crayons. Markers are brighter, but crayon will work. (Note: While they are coloring the fish, explain to them the meaning of the Greek letters on the side of the drawing, and tell the children what Jesus meant when he said to Saint Andew and Saint Peter, “I will make you fishers of men” — and that all Christians are called to withess, to spread message of salvation through Jesus Christ to others, as the apostles and disciples did.) 
3. Wad up the paper towel and dip it in a saucer containing a small amount of oil, and apply the oil all over the colored drawing generously (but not dripping), letting it soak into the paper. Use a dry paper towel to remove excess oil. The oil will make the paper translucent, giving it a stained-glass effect.
4. Cut out the fish and make a small hole about half an inch from the top. Cut the yarn or ribbon about 12″ long and thread it through the hole, then tie it to make a hanging loop.
5. Hang the Christian fish in a window so the light can shine through it, where it will be a daily reminder during the season of Advent of our life as Christians permeated by the Light of Christ.
