The Talmud in (Avodah Zara 16b–17a) brings that Rabbi Eliezer was upset that he had been accused by the Romans. His student, Rabbi Akiva suggested that perhaps he had heard a teaching of the minim and got pleasure from the teaching Rabbi Eliezer confirmed this.
According to this, what would constitute "teachings of the minim" which is forbidden to read or hear or watch, etc. today?