Following the release of Rocky IV, a joke was making rounds in Hollywood. Since Rocky had run out of opponents, he would have to fight an alien if a fifth movie was made. Jim and John Thomas took the joke seriously and wrote a screenplay based on it, which later became the movie "Predator".
After Hitler ordered the deportation of Denmark's Jewish population, Danish citizens organized a massive evacuation of the Jews to neutral Sweden, despite the risks. In the end, 99% of Danish Jews survived the Holocaust.
Google's founders were willing to sell to Excite for less than $1 million in 1999, but Excite turned them down.