Dan is visited by Ludwig Van Beethoven (Jack Black), who shares the lyrics to his most famous compositions.
His guest from the past is Ernest Hemingway (Scott Adsit). Dan and Hemingway get to know one another and spend the day drinking, fishing, and fighting.
His "guest" from the past is Thomas Edison (Jason Sudeikis). Edison becomes obsessed with his legacy and Dan helps him update his history
His guest from the past is Mary Wollstonecraft (Aubrey Plaza). Dan introduces Mary to his girlfriend and gets a lesson on feminism.
Dan is visited by William Shakespeare (Thomas Middleditch) and gives him lesson on modern entertainment.
His guest from the past is Idi Amin (Ron Funches). Idi gets power hungry and Dan and Spencer end up victims of a coup d'etat.
His "guest” from the past is Betsy Ross (Sarah Silverman). Betsy takes an interest in the 2016 presidential election and lends her flag-making talents to one of the candidate’s cause.
His guest from the past is Amelia Earhart (Kristen Schaal). Amelia sets off on a quest to find her earlier lost self.
His guest from the past is Sigmund Freud (Nick Kroll). Freud gives Dan and Spencer an impromptu therapy session to work on their issues.
His guest from the past is Edgar Allan Poe (Paul F. Thompkins). A visiting network executive (Mary Lynn Rajskub) takes a liking to Poe, and Dan uses him to win her over.
His guest from the past is Buddha (Danny Pudi). Dan uses Buddha to integrate products into the show with unexpected results.
His guest from the past is John Wilkes Booth (Andy Dick). To test Booth's acting abilities, Dan casts him as Abraham Lincoln in a play.
His guest from the past is Ada Lovelace (Gillian Jacobs). Ada, the world's first computer programmer, takes a liking to Spencer and the two of them embark on a journey.
His guest from the past is John F. Kennedy (Dana Carvey). Dan, Kennedy, Spencer, and the whole Great Minds team are threatened by an unwanted visitor.
His guest from the past is Harry S. Truman (Matt Walsh). Dan takes Truman to a gay bar to teach him a lesson on gay rights.
