The author mentions the popularity of fantasy and sci-fi books, particularly highlighting C programming language as an interesting choice. The author expresses interest in creating a similar graph for other popular series like The Hitchhikers Guide to the galaxy, The Lord of The Rings, or The Foundation Series, with the goal of winning a Neo4j Community shirt. This is presented as a challenge, encouraging others to take on the task and share their results on Twitter using the hashtag #geek5.