Modern Christmas celebrations are full of pagan symbology. Santa Claus is the Holly King, the sleigh is the solar chariot, the eight reindeer are the eight Sabbats, their horns represent the Horned God, the North Pole symbolizes the Land of Shadows and the dying solar year, and the gifts are meant both to welcome the Oak King as the sun reborn and as a reminder of the gift of the Holly King, who must depart for the Oak King to rule. 

The Giving of Gifts 
Gift giving seems to originate in another December holiday. The feast of Saturnalia (which honored the god Saturn) was long established by the Romans before they invaded Britain, and was celebrated from December 12-17. It was a time when masters waited on servants at mealtime, and gifts of light were given, particularly candles (this may have been in honor of a solar deity for the upcoming solstice). Other traditional gifts exchanged were coins, honey, figs, and pastry.  The giving of coins predates the traditions in England of handing out coins to the less fortunate, or the opening of a lord's purse to feed his household servants. These Roman customs surrounding the use of candles, and the exchange of gifts at midwinter, shows that many later yuletide traditions may have originated in the older festival of Saturnalia. It may also be where the tradition of wassailing and caroling door to door, in expectation of gifts of money, arose, but many of these customs developed somewhat naturally over the years out of various practices by both the nobility and the peasant classes of England. 

The Yule Log 
The familiar carol 'Deck The Halls With Boughs of Holly' still preserves the ancient pagan meaning of the Yule Log: 
 

To pagans everywhere, the Winter Solstice is seen as the death of the old solar year and the birth of the new and as such is celebrated with fire. Traditionally, the Yule Log is Oak and its burning symbolizes the blazing forth of the newborn Sun. The log is lit with an unburned portion of the previous years log, thus symbolizing the continuity. The ashes of the Yule Fire are magickal too and a small portion are kept to bring fortune and protection to the home and the family all year round. These ashes are then sprinkled in the hearth before the next Yule Log is kindled. 

Mistletoe 
Mistletoe was sacred to the Druids who gathered it from the high branches of the oak with golden sickles. White linen cloths were spread on the ground so none of the mistletoe would touch the earth. (Once a magickal plant has touched the ground its powers return to the earth)

It was gathered not only at Yule, the shortest day of the year, but also on the longest day - Midsummer. Gathered at Midsummer, mistletoes does not have any berries and was collected for amulets of protection, whereas mistletoe gathered at Yule bears the white berries that make it an amulet of fertility. Mistletoe is evergreen, and its rootlets are golden, symbolizing the Sun. Its translucent white berries are said to represent the semen of the Lord of the Forest. Kissing under the mistletoe is thought to ensure fertility. 

Herbs
Sun plants like mistletoe, balsam, and fir, and also any dried herbs from Summer, are predominant this time of year because they contain light and warmth. On Yule, when witches decorate their houses, they do so from the doorway inward, this inviting the light inside. We  adorn doorways and mantles with evergreen boughs, bunches of dried summer herbs and Witches cords in reds, blacks, greens, and golds. Our ancient ancestors brought an evergreen tree inside to mystically ensure there would be light all year round. The evergreen retains sunlight, staying green all year, and reminds us that life is forever present and renewable. 

Other Yule herbs, plants, flowers and seeds: 
holly, mistletoe, pine cones, pine needles, oak leaves, 
Yule log ashes, fir, birch, hazel bark, sandalwood, ivy, 
comfrey, elder, cinnamon, cloves, nutmeg, chamomile, 
sunflower, frankincense, myrrh, wintergreen, apple leaf, 
dried apple 

Wassailing 
In areas where other fruits were the important crop (like apples in England), many rituals developed around blessing the orchards at Yuletide. Called "saining," these rites blessed fruit trees and livestock so that the season ahead might bring an abundance of  food. Wassailing, for example, is a well-loved custom and the term wassail comes from Ves heill, Norse for "be in good health". Wassail is a drink consisting of ale, cider, and/or wine sweetened with sugar and flavored with citrus and spices. This brew is traditionally served in a large "wassail bowl," garnished with small roasted apples and ladled into serving cups. Slices of toast might also be set to float in the bowl, later to be offered to the tree. In places where cider orchards flourish, there is the ritual of wassailing the trees, by pouring libations and sticking the cider soaked  toast in the branches of the apple trees. Shotguns are then fired to drive away harm and traditional wassailing songs are sung. 
 

10 small apples  10 teaspoons brown sugar  2 bottles dry sherry or dry  Madeira  1/2 teaspoon grated  nutmeg  1 teaspoon ground ginger  3 cloves  3 allspice berries  1 inch stick cinnamon  2 cups superfine sugar  1/2 cup water  6 eggs, separated  1 cup brandy

Core the apples and fill each with a teaspoon of brown sugar. Place in a baking pan and cover the bottom with 1/8-inch of water. Bake in a 350-degree oven for 30 minutes or until tender. Combine the sherry or Madeira, nutmeg, ginger, cloves, allspice berries, cinnamon,sugar and water in a large, heavy saucepan and heat without letting the mixture come to a boil. Leave on very low heat. Beat the egg yolks until light and lemon-colored. Beat the whites until stiff and fold them into the yolks. Strain the wine mixture and add gradually to the eggs, stirring constantly. Add the brandy. Pour into a metal punch bowl, float the apples on top and serve in 8-ounce mugs.

Campanelli, Pauline, Wheel of the Year, Llewellyn Publications 1997
Moorey, Theresa, Paganism, A Beginners Guide, Hodder and Stoughton 1996
Kightly, Carlo, The Perpetual Almanac of Folklore, Thames & Hudson 1987