Fact: Checked!

Jingle Bells Was Originally A Thanksgiving Song

This was said by a co-worker randomly. Doing my normal job, I had to check it out and found the following from howstuffworks.com:

"...the original music, composed by Boston Sunday school teacher James Pierpont, was conceived as a Thanksgiving song in 1857. Originally titled "The One Horse Open Sleigh," the song was taught by Pierpont to his pupils for a performance and was delighted to find that all 40 of them learned its lyrics almost immediately. Declared "a merry jingle" by a close friend, this holiday carol was fine-tuned and performed again at Christmastime, and quickly became a Yuletide classic."