In case you were asking, and you shouldn't have been because this game deserves to be savored a bit longer, it's December 10.
That's when the Kansas City Chiefs and Oakland Raiders play each other again, in case Thursday night wasn't good enough for you.
And while there are some folks who won't be happy (those who like the Chiefs or bet the Chiefs), there won't be a more magnificently bizarre game this NFL season – because these two teams are exactly that.
The Chiefs, who two weeks ago were the best team in football as voted on by the instant punditocracy, made enough mistakes in the last two minutes of Thursday's 31-30 defeat to lose 47-10.
And the Raiders did the same, capped off by Marshawn Lynch's gloriously Oaklandish reaction to fellow citizen Marcus Peters' late hit on Derek Carr – namely, "I got your rules and your respect for officials right here!"
But in the end – the glorious, bizarre, untimed end – the Raiders saved themselves from pre-Halloween doom, the Chiefs reverted to the team you can never fully trust, and the rest of the NFL can only shake its collective neckless head in wonderment at the power of the old American Football League.
Because that, ultimately, is what this was – a game out of time. This was a throwback game, all the way back to the mid- to late-60s, when the Raiders and Chiefs hated each other not out of historical duty but out of genuine solar-generated animosity. When they both played as though their cars were being looted in the parking lot, and when 750-yard combined passing nights were actually not that unusual. They were hell-bent then, and Thursday showed that they still have that bent in their DNA even now.
This was that era, played out in a way that old Raider and Chiefs fans can tell their grandchildren, "Now you're sitting there scratching your head and all, but I'm telling you that used to happen all the time. You think Marcus Peters was bad? Google Ben Davidson on Len Dawson, little Tad."
And it ended the only way it could for the good of the rivalry – with Oakland winning, and in the most staggeringly improbable way.
Not because the Raiders are more noble human beings or a superior life form from a time long ago, but because that December 10 game needs to mean something. The Raiders needed to win Thursday because losing meant their playoff hopes would be deservedly dead, and their remaining nine games would be reduced to competitive afterthoughts, and the year would be reduced to wondering why what should have been never came close to happening.
And the Chiefs needed to lose because running away with a division this difficult just seems wrong. There is nothing that says Kansas City isn't better than Denver, or Oakland or the Fightin' StubHubs, but it shouldn't be this easy. The Patriots may have eaten the AFC East and spit the bones into a dumpster long ago, but the AFC West clung harder to its AFL roots than the East ever did.
And Thursday was the evidence required to show that, at least for the Chiefs and Raiders, the old days can be recreated with a keen eye for the most malevolent details and the most bizarre turns of fortune.
Call it nostalgia on crank – seemingly the only thing we have left that can bond the generations in these otherwise mean-spirited days.