God calls each one by name (Cf. Is 43:1; Jn 10:3). Everyone's name is sacred. The name is the icon of the person. It demands respect as a sign of the dignity of the one who bears it. (#2158, Catechism of the Catholic Church).
What is a Nameday?
A Nameday is the feast day of our Patron Saint. This begets another question: Who is my Patron Saint? [The Church has honored some] men and women who have lived through the centuries in such a holy manner as to have been declared by the Church to be Saints or Blesseds. If we bear the name of one of these, this Saint is known as our Patron. Each Saint has been assigned a feast day by the Church. The feast day of your Patron Saint will be the day on which you celebrate your Nameday. (My name day is July 26th. :D)
For centuries it has been the custom in Catholic countries to celebrate Namedays even more than birthdays. This tradition is still very much alive in Europe and South America, and continued to flourish even during times when religious freedom was curtailed.
Immigrants to Canada and the United States from countries that observe Namedays are already carrying on the practice in North America in the same way they did while they were in the country of birth...
Socially, cards and small gifts of flowers or candies are usually given to those celebrating their Nameday. Spiritually, one would normally have a devotion to one's Patron Saint, and pray to them regularly, especially when in need. A Patron Saint, we can be sure, will be watching over those named in their honour, and will be protecting them in a special way.