During the scene where Klaus chides Stan for having his body switched with that of a goldfish, there is a flashback to the Olympic skier who received the fish's brain. The sign at the top of the ski jump reads "1986 Winter Games." There were no Winter Games in 1986! The writer or animators made this mistake because up until 1992, the Summer and Winter Games were held in the same year and not 2 years apart from each other as was done later. Thus, the writer/animators intended for this to most likely be the 1984 Winter Olympics but forgot NOT to adjust for the 2 year's difference.
In addition, Stan said that the brain switching was done to prevent East Germany from winning the gold medal. But, East Germany DID win a gold medal in Ski Jumping - Normal Hill in 1984; they did not win gold in Large Hill, but did get silver. So, Large Hill might have been the event animated for the scene. (If they meant 1988 instead, East Germany didn't win the gold, but did win a medal in Nordic Skiing - Men's.)