Okay kiddo, so the Heidi Game happened a long time ago in 1968. It was a football game between two teams, the New York Jets and the Oakland Raiders.
Now, this game was a special game because it was going to be broadcasted on TV for everyone to watch, which wasn't very common back then.
But during the game, something crazy happened - the TV station that was broadcasting the game had to go off the air because they had promised to show a movie called Heidi after the game.
But that meant that people who were watching the game couldn't see the end of it! And that made a lot of people really upset.
The game ended up being really exciting - the Raiders scored two touchdowns in the final minute of the game and they won! But a lot of people didn't get to see it because they were tuned into the Heidi movie instead.
And that's why people still talk about the Heidi Game today - because it was a time when TV broadcasting was really different from what we're used to now, and it caused a lot of confusion and frustration for football fans.