According to German Traditions the pickle brings good luck and is the last ornament to be placed on the tree.
On Christmas morning the child that finds the pickle was rewarded from St Nick with an extra gift. The German tradition was so that the children would enjoy all the ornaments on the tree besides the gifts from St. Nick.
Ok, so thats not reality! I started this tradition with my girls, as my Great Grandfather was from Germany. Oh and let me tell you the completion on Christmas morning to find the pickle, well you can imagine. To my Horror they would almost tear the tree to shreds! Isn't it great to make those holiday memories... Ho Ho