While the ethnic diversity of New York City is apparent all year, it is joyfully obvious during the Christmas holiday season, when the customs one finds throughout America are flavored with traditions these groups have retained from their lands and cultures of origin.

Just prior to Sunday Mass at Our Lady of Czestchowa Roman Catholic church, a highly traditional Polish parish deep in the Park Slope section of Brooklyn, choirmaster Pawel Raczkowsi makes sure his singers have the old country's carols just right.

Jane Matuszewski loves that music. She was born in Poland but came to America as a young girl. She is proud of her adopted homeland but still enjoys some of the Old World customs, beginning - she says - the night before Christmas. "Christmas already starts on Christmas Eve. Because here usually [in the U.S.] Christmas Eve people are still shopping. But with us, once the first star is seen, it's already Christmas for us? And the table is set in white. And the family members in Poland, you remember them." She laughs as she explains that sometimes she calls them before sitting down to Christmas dinner. " Because there is like six hours' [time] difference, so when we are ready to sit, they are going to Midnight Mass already!"

Some Polish customs, such as the placing of straw from the church manger scene under the tablecloth, seem to have rural peasant roots. But Ms. Matuszewski says most derive directly from Catholic Church rituals. She considers them very spiritual, very holy. "At the dinner on Christmas Eve, the most important thing is the breaking of the wafer. We have what is called the Oplatek." Her fellow choir member, Ilene Glodowski, chimes in, "It's a square made of unleavened bread like the Host and it's blessed but not consecrated." "Usually the father will pass one to the mother," explains Mary Donderewicz, who also sings in the choir, "and they break the wafer and they pass it on to their children and whoever guests there are, and they wish each other God's blessings and lots of luck and whatever they need to survive." The Oplatek is part of one of Ms. Glodowski's favorite Christmas traditions. "I was born here and my parents were born here," she says, "but there are still cousins and relatives over in Poland, and in the Christmas cards, everyone puts [in] a wafer, and it gets sent over there. So you are even breaking bread with your relatives on the other side of the Atlantic, which is a nice tradition too. By sending a wafer to your relatives on the other side, it connects you."

At a Norwegian holiday festival, carols mingle with calls of God Jul, or Merry Christmas. And food is an important part of the celebration. As they nibble on their second or third or fourth krum kake, two women explain the appeal of this traditional Norwegian Christmas cookie. "It's like a cone," says one. "It has a vanilla taste to it. And they are good. Delicious!" Her friend points out, "You can have ice cream inside or whipped cream on the side." She remembers her mother baking traditional holiday treats. "She also baked bread during the season. And the porridge, the rice porridge."

In fact, tonight's traditional celebration, called a grutfest, is named for that rice pudding. Roy Andersen - who, at forty-eight, may be the youngest member of this once-thriving Norwegian congregation - points to a large, steaming platter of the delicacy, which is being ladled into bowls throughout the room. He says it's really a simple dish. "It's rice that is cooked with milk and stirred for many, many hours. And there is a little nut that is placed in the bowls, and the one who gets the nut gets the prize. So fun little things like that I remember growing up with." He glances around the room at his fellow churchmembers. "It's an interesting group of people. We are low-key in a lot of ways, but we are warm, friendly, loving people, and we love all kinds of people."

There is nothing low-key about parandas, a Puerto Rican holiday custom practiced by Big Apple Latinos. In a tradition that seems to combine the best of Christmas and Halloween door-to-door trick-or-treating, friends or family members show up unexpectedly, late at night, at a loved one's home to play music and sing traditional carols. In return, they are offered hot drinks and sweets.

For 12-year old Camillo Bolina, the paranda has come to mean the Christmas Season. "Once it hits December, from December First to January Second, it's all parandas," he says. "I usually do at least once paranda every year. And I also do my Christmas thing. I go to my aunt's house or Christmas Eve and hang out and have Christmas dinner, and wake up Christmas day and open presents. But, as much as I like to do that, I like to do this stuff, too. Because this is what they used to do -- and they still do -- in Puerto Rico now. So it's like a little bit of Puerto Rico here in New York!"