What is the "Heidi Game" of 1968 remembered for?

Which kicker is the NFL's all-time leading scorer? Which Bills kicker missed a potential game-winning field goal wide right at the end of Super Bowl XXV? Which Eagles tight end threw the touchdown pass on the "Philly Special" in Super Bowl LII? What happened with the "Tuck Rule" in the January 2002 playoff game between the Patriots and Raiders? What is the "Fog Bowl"? In what year did the NFL expand its regular season from 16 to 17 games? In what year was the two-point conversion adopted by the NFL? What happens if an NFL regular-season game is still tied after the 10-minute overtime period?