One text that is always a pleasure to teach is Cervantes's Don Quijote. In the Survey of Spanish Literature course, students respond with a varying degree of enthusiasm to the readings we do. Don Quijote, however, always receives a great response whenever and wherever you teach it. At first, the students might be a little wary of the text because of its complexity, but as soon as we begin analyzing it, they start brimming over with questions, ideas, suggestions, etc. I always prepare to finish the lecture a few minutes earlier because I know from experience that after a class on Cervantes students will be unwilling to leave the classroom.
It's overwhelming how a text published in 1605 (we only discuss excerpts from the first part in this survey course) can resonate so deeply with kids of the XXI century. Nothing makes me happier than seeing students get so excited about a work of literature. It is so rewarding to be able to share my love for Cervantes with the younger generation, to introduce the students to this great novel.
If you are teaching (or preparing to teach) this text and don't know how to get the students involved in a discussion about it, my advice is to start with the names of the characters. Don Quijote, Sancho Panza, Dulcinea, Rocinante - these names offer such a wealth of information and so much food for thought that an entire lecture can be dedicated just to them. And students love this discussion and respond with a multitude of questions to it.
I feel very elated right now.