The iconic Penny Arcade mug shot was only meant to serve as b-roll for the pilot, but was spotted by the editor and used as the title shot for all subsequent episodes.
The "Book Tour" episode begins with a phone interview. Lev Grossman, who later appears in person in the "Time 100" episode, is the person conducting the interview.
In "The Show" episode, we see the film crew that took over for Season 2 get hired. Following the "Season Finale" episode, all episodes are handled by this new crew.