Christmas is in its current form very much a Pagan holiday. The Christmas tree is a remnant of Pagan tree worship which many Pagans still embrace today. For Pagans who follow Wicca, Heathen and Celtic paths, the Winter Solstice is called Yule and it falls on the 21st or the 22nd. For those who follow Hellenic paths, Saturnalia falls on the 25th. The exact mythology surrounding these holidays varies by traditioni. For some it celebrates the rebirth of the Sun God, for others it celebrates his victory over a usurper. Either way it is a festival celebrating the shortest days (and longest nights) of the year and the promise that we'll soon be seeing more of the sun.These holidays are celebrated by decorating with greenery (including trees), lights and sparkly things. We have feasts, with traditional foods like puddings, pies, winter squash, potatoes, candied sweet potatoes, green bean casserole, cranberries and, for those of us who are not vegetarian, ham, turkey, goose, duck or fish. And of course lots and lots of cookies. For many, the celebration also consists of staying up all night to watch the sun rise. Many of us also enjoy giving gifts this time of year as a way of giving thanks for the people who make our lives rich.
That all being said, some of us do celebrate Christmas, and call it such, in addition to our more traditional celebrations. For us, Christmas is secular and Midwinter Night is the religious holiday.