One of the interesting cultural quirks that I discovered while living in South Korea is that instead of aging a year on your birthday, people are considered one year old when they are born and then age one year on every Lunar New Year's Day.
For example, in the Western world if a child was born on December 31, 2011, they would not be considered one year old until December 31, 2012. In South Korea, a child born on December 31, 2011 would be considered one year old on that day and than age a year in January. They would be considered two years old on Lunar New Years Day, when in fact they are only a few days old by Western standards.
My South Korean friends used to tell me that they loved visiting North America because, in the Western world, they are younger than they are at home.