Thanksgiving Football

Thanksgiving postcard circa 1900 showing a turkey and football player. 

American football is one of the many traditions in American culture that is associated with Thanksgiving Day. Virtually every level of football, from amateur and high school to college and the NFL (and even the CFL on Canadian Thanksgiving), plays football on Thanksgiving Day (Thursday) or the immediately following holiday weekend (Friday, Saturday and Sunday).
Thanksgiving Day football games in the United States are nearly as old as the game itself.
The first Thanksgiving Day football game took place in Philadelphia, Pennsylvania on Thanksgiving Day of 1869, less than two weeks after Rutgers defeated Princeton in New Brunswick, New Jersey, in what is widely considered to have been the first American Football game.
On November 17, 1869, the Evening Telegraph newspaper of Philadelphia published the following announcement: "Foot Ball: A foot-ball match between twenty-two players of the Young America Cricket Club and the Germantown Cricket Club will take place on Thanksgiving Day at 12 1/2 o'clock, on the grounds of the Germantown Club."
The proximity of Philadelphia to both Rutgers and Princeton invites speculation that this game may have been played under similar rules and perhaps involved some of the same participants, or at least people familiar with the game played at Rutgers, and a second match at Princeton, earlier that month.
Princeton played Yale in the New York City area on Thanksgiving Day from 1876 through 1881. 
The Thanksgiving Day football game became an institutionalized fixture of organized football in 1882, when the Intercollegiate Football Association determined to hold an annual collegiate championship game in New York City on Thanksgiving Day between the two leading teams in the association.
Previously, the 'Champion' was to be determined by a team's records over the entire season against all members of the association.
For at least the three previous years, the championship had been a matter of dispute as a result of Yale and Princeton playing to scoreless ties on three Thanksgiving Day games in a row.
The tradition of playing football games on Thanksgiving continues to this day.