The ceremonies mark the passage of time in the utopian society in which Jonas lives. They occur every December and take the place of birthdays. For children up to the age of twelve, these ceremonies are a sign of their maturity, and they bring new responsibilities and/or the loss of certain objects. Although these phases of life are normally highly-emotional and individually celebrated in our society, they are rigidly controlled as natural progressions in life.
The ceremonies are significant because they stand for a few celebratory events at the same time. The ceremonies take the place of birthdays, so in a way the ceremonies are a method of marking time. Instead of everybody having their own birthday, each person ages "one year" when the ceremony occurs. The ceremonies signal to the children that they are now another year older. Each ceremony and extra year of age brings with it new responsibilities. At each age, a child is given a new item or has an item taken away from them. Those items are meant to teach lessons during that year of life. For example, one of the items given is a jacket that buttons in the back. That teaches the children the importance of being dependent on other people. A few ceremonies later, the jacket is replaced with one that buttons in the front. The final ceremony is the ceremony in which each child finds out the role that he/she will perform in society. This final ceremony is similar in concept to a graduation ceremony.