Dr. Seuss wrote Green Eggs and Ham as part of a bet.
The idea that a man should spend two months salary on an engagement ring was popularized by De Beers' ad agency.
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".