At this time of the year, I have the first graders listen to The Polar Express by Chris Van Allsburg read by Lou Diamond Phillips at Storyline Online at the beginning of class. Then they each create a passport of their own using ReadWriteThink's stapleless book maker. You can include the names of the countries you are going to be learning about during your trip around the world in your passport. Before the students leave, I give each of them a ticket to board the Polar Express and tell them that they'll need to bring the ticket to the next class when we will be traveling around the world to learn about Christmas and other holiday traditions in other countries.
If you wanted to make this lesson more exciting, you could find schools in other countries to Skype with. The students at these schools could tell your class first hand what some of their holiday traditions are. I'm making this a goal of my own for next year!