Because the Winter Solstice is the turning point of the year, beginning the lengthening of days, it has long been viewed as the birth of the year--by pagans celebrating the return of the Sun, and by Christians welcoming the birth of the Son of God. The days between Solstice and the New Year are a magical, luminous time period, when anything is possible. In England, the Twelve Days of Christmas were considered omen days which could be used to predict the weather in the coming year. In Scotland, no court had power during these days; and in Ireland, tradition held that if a person died during the Twelve Days, he or she went straight to Heaven.
In ancient Babylon, the days between the Winter Solstice and the New Year were seen as the time of a struggle between Chaos and Order, with Chaos trying to take over the world. Other cultures (Hindu, Chinese, Celtic) also viewed this as a time for reversing order and rules-celebrants would change roles with servants or dress in costumes for a time until order was restored.
Starting Fresh
While each culture's New Year celebration has its own flavor, there are certain common themes. The period leading up to New Year's Day is a time for setting things straight: a thorough housecleaning, paying off debts, returning borrowed objects, reflecting on one's shortcomings, mending quarrels, giving alms. In many cultures, people jump into the sea or a local body of water-literally washing the slate clean.
In some towns in Italy, I've been told, you have to watch out for falling objects, as people shove their old sofas, chairs and even refrigerators out of their windows on New Year's Eve. In Ecuador, people make dummies, stuffed with straw, to represent the events of the past year. These "ano viejo" effigies are burned at midnight, thus symbolically getting rid of the past.