Incognito
In 2005 students at MIT hosted “party” invited time travellers from the future to show up. This caused a minor blip of amusement to go across the mass media of the time since nobody from the future showed up. It was more amusing many years later when it was revealed that the entire party had been staged by people who had managed to find their way into the school from many years in the future. I wasn’t there but I saw the joke in it.