Schmirinski's: Fiesionen (2000)

The story of "Fiesionen" begins in a retirement home in the year 2050... Schmidi and René reside there and, unsurprisingly, continue to cause all sorts of excitement. When the inventor of the time machine, Prof. Dr. Dr. Dr. Steissbein, visits his childhood friend and nursing home director Prof. Gräulich, they spontaneously decide to punish the two incorrigible troublemakers for their inappropriate behavior by sending them back to the bad old days as guinea pigs. The two sly foxes, marked by a dreary and colorless future, decide to use the opportunity of their trip into the past to make the future more joyful and positive again. Through their entirely unselfish persuasion in our present, they hope to bring about a change in humanity's thinking. This should have a favorable influence on their own future in the retirement home.