The Screwtape Letters is hilarious. They were given hand-to-hand in my teenage years, when religious literature wasn't easily awailable over here, and we discussed it endlessly with the Catholic youth group I belonged to. We also howled with laughter each time the topic came up.

When I was in novitiate, we had a meeting with the young people from other orders. One such group turned parts of the book into a performance - it was rather chilling, surprisingly enough.