The book Colleen is reading when Liz visits her is entitled "Urban Fervor", the sequel to the fictional novel "The Rural Juror" in which Jenna stars in the movie adaptation.
The Glovers, the family for whom Liz buys gifts, take their name from writer/story editor Donald Glover.
The man playing the piano during the Christmas special, shown while Jenna is singing, is musician/producer Jeff Richmond, husband of Tina Fey.
When Jack hits Colleen with his car, the shot of her legs sticking out from behind his car clearly mirror the shot of the legs of the Wicked Witch of the East after Dorothy's house lands on her.
Frank's hat reads "Foley Artist", making it go well with his T-shirt, one of professional wrestler Cactus Jack, real name Mick Foley.