Baseball and the Civil War have long been linked – erroneously – thanks to the myth of Abner Doubleday’s “invention”, but it has a tie far more interesting than the fictional one:

One hundred forty-nine years ago, two teams made up of members of the Union Army faced off against each other in a Christmas Day baseball game in Hilton Head, South Carolina. The Civil War is widely credited as having been a factor in spreading baseball across the country, and historical records exist for a number of the games played during the war — Baseball Almanac notes at least five in 1862 alone. The Christmas Day game was probably the best-attended game of the war, perhaps one of the best-attended games of the 19th century. But we don’t know that for certain, or indeed much of anything about the game, not even its final score.

One reason for the confusion is the unreliable source at the heart of the story. The game’s most famous player was A.G. Mills, the namesake of the Mills Commission, which established Abner Doubleday as the “founder” of baseball and Cooperstown as its birthplace on the basis of virtually no evidence. Mills played in the game when he was an 18-year old private with the New York Volunteers…

http://www.fangraphs.com/blogs/index.php/the-civil-warchristmas-day-game-hilton-head-1862/

Some interesting facts from Wikipedia, on this Christmas Eve:

Christmas in the American Civil War (1861–1865) was celebrated in both the United States and the Confederate States of America although the day did not become an official holiday until five years after the war ended… In 1870, Christmas became an official Federal holiday when President Ulysses S. Grant made it so in an attempt to unite north and south.

For children, Christmas was altered during the war. Presents were fewer, especially in the devastated South. In We Were Marching on Christmas Day, author Kevin Rawlings notes that some southern children worried about the Union blockade, and one little girl, Sallie Brock Putnam, plotted the course Santa Claus would have to take to avoid it… Excuses for a lack of Santa included Yankees having shot him.

And, my favourite:
In one incident on December 25, 1864, 90 Union soldiers from Michigan, led by their captain, dispensed “food and supplies” to poor Georgians, with the mules pulling the carts decorated to resemble reindeer by having tree branches tied to their heads.

Merry Christmas!

http://en.wikipedia.org/wiki/Christmas_in_the_American_Civil_War