In "The Legend of the Gobblewonker," when Stan takes Dipper and Mabel fishing, part of the planned 10 hour bonding activities is reading from the joke book. Stan holds up "1001 Yuk 'Em Ups" and says: "I brought the joke book!" According to the cover, the book is "Uncle Approved!" Dipper and Mabel dislike and are obviously afraid of the jokes in the book.
Later in the episode, after Dipper, Mabel, and Soos decide to come back to Stan, Stan decides to read the book to them afterwards. After reading one of the jokes, Soos and Grunkle Stan are the only ones who find the jokes to be funny.
The joke book is a shorter than average book, also known as "humorous size." It has a dark red color and cylindrical-shaped spine of the same color along with two yellow stripes. On the front are white words that read "1001 YUK 'EM UPS." Below that is an elderly man with a quote bubble beside him that reads, "UNCLE APPROVED!"