Christmas Eve is known as Sviata Vechera in the Ukraine, and the 
following is a description of their celebration.  It is from the 
cookbook "Festive Ukrainian Cooking" by Marta Pisetska Farley.

The traditional year for the Ukrainians started with the great period 
of abstinence called Pylypivka (Advent).  By fasting on certain days 
and restraining from dancing, Ukrainians prepared themselves for 
Christmas and its celebration.  Until quite recently, Ukrainians 
celebrated the Christmas season from Christmas Eve (January 6, O.S) 
to the Feast of Jordan (January 19, O.S.).  The Birth Of Christ 
(Rizdvo Klustove) started the church calendar for Uniate and 
Orthodox Christians alike.  As with many great feasts, the eve 
(navecherie) preceding the day marked the beginning of the 
celebration.  Christmas Eve ended with Holy Supper (Sviata Vechera). 
However there was much preparation beforehand.  Before partaking of 
the Christmas Eve meal, the family fasted all day.  The house was 
put to order, but no outside work was done.  All members wore 
festive clothing.  This was a holy day.  The tone of the supper was 
that of "festive dignity".  The meal officially began with the 
sighting of the first star, a task assigned to the children.  The 
male head of the household (hospodar) took a bowl of Kutia 
(flummery) and invited the should of all the departed family members 
to partake of the meal.  He invited the forces of nature to share in 
the meal and to protect the family from natural calamities in the 
coming year.  Specific rituals and spells to placate nature's fury 
differed regionally.  One important ritual that prevailed in many 
households was the communal sharing of bread and honey.  The 
Hospodar to a plate with small pieces of kolach and a dish 
containing honey and salt and dipping each piece of bread lightly 
into the honey, approached each member of the household, starting 
with the eldest.  "Chrystos razhdayet'sia" ("Christ is born"); he 
was answered "Slavite Yeho" ("Let us glorify Him"),  The female head 
of the household (hospodynia) repeated the greeting.  After that the 
supper began, dish following dish, ending with kutia or uzvar, 
depending on which one began the celebration.  Each family in each 
locality developed its own adaptation of this meal, so that there 
were many variations on a basic theme.  After the meal, the hospodar 
visited the barn animals and added kutia to their food.  This 
custom reflected the strong belief that the dish had magical 
properties far greater than the sum of the ingredients would 
suggest.  The animals were believed to be endowed with speech on 
Christmas Eve, as a gift from God for their service to the Christ 
Child on the night of His birth.  Other ritual activities were 
important ot varying degrees in different regions.  The menu for 
Sviata Vechera varied from province to province in execution and in 
order of presentation.  The number of dishes ranged from twelve 
(most common) to nine or seven.  Each number had magical 
associations.  The table was set with specific items.  The table was 
strewn with hay, symbol of fertility and abundant harvest, then 
covered with a cloth.  A large kolach flanked by candles, was placed 
in the center of the table.  A dish of salt and a dish of honey were 
put at the host's place.  On a sideboard, a lit candle with a dish 
of kutia commemorated the family's dead.  An extra place for the 
unexpected guest remained set until the end of the meal.  A sheaf of 
wheat, symbol of abundance and nature itself, graced a corner of the 
room. 

Christmastime lasted three days, January 7-9 (O.S.).  Guests and 
neighbors were invited to visit on Christmas Day and on the second 
and third days of Christmas.  Treats were numerous, primarily nuts, 
sweet cookies, or rolls.  Visits were frequent and convivial.  Among 
all the groups of people, caroling was the main outdoor activity. 
Koliady and shchedrivky were sung throughout the Christmas season, 
an ancient practice probably traceable to Roman influence.  Every 
peer group - Hospodari, hospodyni, girls, and young men - went about 
the village or town and greeted each household with these seasonal 
songs.  Each group had its own appropriate repertory that differed 
from region to region, but the custom of caroling was all pervasive. 
Koliadnyky (carolers) were invited into the homes and given treats, 
food and drink; horilka (whiskey) to hospodari, nuts and fruits to 
the boys and girls.  Today, in the United States and Canada, koliada 
is used as a vehicle through which Ukrainian charities solicit 
donations.  The gift now is money.  Children and young adults still 
visit Ukrainian homes and sing the ancient "Bob Predvichnyi" ("God 
Eternal") and receive traditional treats.  Christmas was followed by 
Mulanka (New Year's Eve), January 13 (O.S.).  The holiday had fused 
with an old celebration know as Shchedryi Vechir (Generous Evening). 
Foods prepared for this evening differed regionally.  In the Dnipro 
area, pies with meat filling and buckwheat pancakes with sausages 
were offered.  In the southern Ukraine, bubyky (small savory rolls) 
found popularity.  In the Hutzul area, in the Carpathain Mountains, 
vareyky were featured.  One old custom for welcoming the new year 
was the practice of zasivannia (sowing).  A young boy took a sack of 
wheat and went from house to house, greeting everyone with the New 
Year, scattering the grain on the floor and reciting appropriate 
verses of good wishes.  For this greeting, he was rewarded with 
coins.  Some housewives hurriedly offered the coins so as not to 
have an excess of "good wishes" to clean up.  Yordan-Vodokhreschenia 
(Jordan-Blessing On The Waters) signaled the end of the Christmas 
celebrations.  On the eve of January 19 (O.S.), a scaled down 
version of Sylata Vechera was served.  This had the popular name of 
holodna kutia (hungry meal).  On the feast day (praznyk) itself, 
after the church service, everyone went to the local stream or river 
where the men had carved a large cross from the river's ice, often 
stained red with beet juice.  There, the cross and the waters were 
blessed by the priest.  This was a combined effort to celebrate the 
Christian feast of Christ's baptism and to "buy protection" from the 
forces of nature from Spring floods. 

Modern Adaptation of Sviata Vechera (Christmas Eve)

The modern adaption of Sviata Vechera is faithful to some of the old 
traditions discussed above.  The house is cleaned, the table set 
with the best china and candles.  One candle and one dish of kutia 
are placed in the window in memory of the souls of ancestors -- or 
more recently, in memory of the Ukrainian soldiers who fought in the 
war for the Ukraine's independence in 1918.  An extra place is set 
for the unexpected guest.  The table is covered by an embroidered 
linen cloth.  A large kolach with Christmas greenery (instead of the 
traditional straw or hay) serves as the centerpiece.  A plate with 
small pieces of kolach and a dish of honey is set at the head of the 
family's place.  In the corner of the room, a Christmas tree 
decorated with handmade ornaments substitutes for the ancient sheaf 
of wheat (didukh).  The same basic dishes are prepared and served in 
traditional order.  Dietary restrictions have been somewhat modified 
by the church, and many cooks cheat a little by including 
ingredients that were formerly banned.  These include eggs, butter, 
and cheeses, which are used primarily in the preparation of kolach, 
pampushky, and fillings for varenyky.  It is very proper for 
families to develop personal adaptions of the basic Sviata Vechera 
menu.  Some families dote on fried fish or marinated herring (a 
perennial favorite).  Some prefer the fancy fish quennelles.  Some 
serve two or three fish courses.  Individual interpretations of 
borsch are also common.  Usually, the borsch served is a full bodied 
but meatless "Ukrainian" borsch, which includes all the vegetables 
and is thickened with zaprazhka (roux).  Some families serve just a 
clear bouillon of beet broth, kvas, and stock with vushka 
(Dumplings) floating on top.  The target number of dishes is twelve, 
in honor of the apostles, or the magic numbers of nine or seven if 
one is superstitious.  The traditional menu adapted usually includes 
braided bread (kolach) with honey, beet soup or broth (borsch) and 
dumplings (vushka) with mushroom filling, fish in aspic, or in any 
other style, stuffed cabbage leaves (holubtsi) with mushroom sauce, 
dumplings (varenyky) filled with mashed potatoes and sauted onions, 
dumplings filled with cabbage and sauerkraut, compote of dried fruit 
(uzvar), flummery (kutia) of wheat kernels with honey, poppy seeds, 
etc., tea with lemon, yeast raised doughnuts (pampushky) with rose 
preserves.