Many thousands of years ago, our American ancestors, the Cowboys, came to this great land seeking freedom from oppression, and cows. They landed on Plymouth Rock and established the first American city, which was probably Boston or Philly or something.
Anyway, when they arrived, the United States was overrun by huge malicious turkeys. Just as prehistoric Canada was controlled by a ruthless cartel of giant beavers (look it up, dude,) ancient America was the stomping grounds of big fat mean cigar-smoking turkeys, who had enslaved the Indians to build for them huge monuments like the Cahokia mounds and the St. Louis Arch and probably the Space Needle and stuff.
So the Cowboys showed up and were like "Howdy pod'ner." And the turkeys go like, "What up? Are you the new slaves we ordered?" And the Cowboys go "I don't think 'at sooooooul brother." And they pull iron on the turkeys and there's this huge battle, which is where George Washington and Abe Lincoln and MacArthur and all those dudes came from, because the Turkeys called in the British to fight for them because there was an ancient treaty but then the British were finally like-- "What are we doing? Without you Hitler is going to take us over!" So then the British came over and helped the Cowboys, and the Indians too, and finally there was just the main boss-turkey in his HQ and he goes "Don't be foolish. You and I are not so different, really. We could be partners and rule these United States together!" And the main Cowboy goes "E pluribus unum" or something like that and shoots the boss-turkey, who flies backwards through a huge plate-glass window and falls like, 100 stories down.
And so now on the last-but-one Thursday of November, we all get together and give thanks for the birth of our country. We have pictures of pilgrims and Indians up all over, because after the war the Indians became the Native Americans, and the Cowboys dressed up like pilgrims for Halloween or something. We have left-over pumpkins from Halloween, too. We eat turkey, which represents our victory over turkeys, and cranberry sauce which represents the blood of our enemies, and yams, which represent sweet potatos. And then we watch football, which represents the Cowboys.