On Ash Wednesday, set a jar out for each child. Each day they can earn a jellybean of any color. Can't eat them until Easter. On Easter morning, fill the jars to the top with white jellybeans (where they are lacking) to represent the Grace of Christ.
The origin of the Christmas tree. My conclusion is to teach that the Christmas tree is a reminder of the tree on which Christ Jesus died. We put lights on it to remind us that we are the light of the world. It points upward to remind us from whence comes our help. We lay gifts under it to remind us of God's gift of his Son.