Someone put up a thread about alternate 70's scenarios, so I will try some Alternate 80's scenarios:
Entertainment:
Rupert Murdoch decides not to go ahead with a fourth major TV network in 1986.
Tom Selleck is cast as Indiana Jones in Raiders of the Lost Ark.
MTV, after consideration, doesn't go on the air in August, 1981. It's launch date gets pushed back to the Spring of 1982.
Matthew Broderick is cast as Alex P. Keaton in Family Ties.
Rap and Hip Hop stay underground, and don't ever fully make it mainstream.
Sports:
On the play after The Catch, Drew Pearson breaks away from Eric Wright and scores a TD, giving Dallas a victory over San Fran in the 1981 NFC Championship game.
The Warriors decide to keep a center named Robert Parish in 1980 instead of trading him to the Celtics.
The Colts decide to trade Elway's rights to the Chargers for their two of their three #1's and Dan Fouts before the 1983 draft. Then, the Chargers decide to trade their third 83#1 to New England for All-Pro CB Mike Haynes.
Steve Rogers doesn't give up the homer to Rick Monday in the 1981 playoffs, and the Expos, with young stars Gary Carter, Andre Dawson, Tim Raines, Tim Wallach, etc.., go on to the WS and defeat the Yankees.
MJ gets drafted by the Houston Rockets after they trade Ralph Sampson to the Blazers for the #2 overall pick, and the Rockets get Olajuwon and Jordan.
The US
President Reagan is shot and killed in 1981 by John Hinckley.
On a January morning in 1986, they decide to not let the Space Shuttle Challenger go up in the air because of the cold temperatures.
Jim Bakker and Gary Hart don't get caught having affairs.