I find that the key to holding adolescents' interest is to make it a subject that they can identify with.
Adolescent students are very ego-centric.
If they don't see what something has to do with them, they are usually not interested. They take turns presenting this in groups. The students will pose a question that deals with the topic given, and how it relates to life. Next, they will pass a cross around the circle, and each student has a chance to share and respond. Many students have commented that this prayer time is their favorite part of class.