"The Barbecue, the Movie, & Other Unfortunately Not So Relevant Material" is a time travel science fiction short story by Harry Turtledove. It was originally published in Analog Magazine in March 1986 and reprinted in the Turtledove collection Departures in 1993.
Lasoporp Rof is a graduate student some fifty to sixty thousand years in the future. As he wants to write his dissertation on the expansion of the Mongol Empire, so he receives permission to use a time machine to travel back and observe Temujin, Genghis Khan. However, due to a temporal phase link drop, he arrives in the 20th century at the Los Angeles office of another Temujin Genghis Kahn by mistake. Kahn, astonished by this, explains that Lasoparop missed his target, but then helps the time traveler out as much as he can under the circumstances.