They played the New York Giants on MNF. It was the last regular season game before they walked out in 1982.

I think GB lost 20-0.

If listening to the radio counts, it would have been the Packers vs. Rams, 1982 season opener - largest comeback in GB history game. My father and I had gone fishing in WI that morning, and listened to the game on the radio on the way home...

First game I have actual memory of watching, though, was the 1981 NFCCG - 49ers vs. Cowboys. The game with "The Catch" (Montana to Clark). Second game would have been Super Bowl XVI - Montana 49ers vs. Ken Anderson's Bengals..