I just watched the video The Case for Christ (2007, 1 hr 11 min). It is the story of how self-described atheist Lee Strobel became a believer by researching the validity of the claims of the New Testament.
This video is a really good resource but it will have far less impact if you just watch it. Personally, if I were going to use it, I'd watch it by myself first and prepare questions for a pre-video discussion asking the students (adults or high school youth) some of the questions Strobel asked. I would include in the discussion problems or questions atheists might have with Christianity. Then I would watch the video and either have questions for afterward or stop it periodically to ask questions. If you don't stop the video I would give students a list of questions or things to pay attention to while they watch. It keeps their minds engaged and gives them an idea of what you think is important or clues them in to some of what may be discussed afterward. The most relevant part of the discussion will most likely come from final questions pertaining to how this video may have changed anybody's thinking or beliefs, things they hadn't known prior, and to give them an opportunity to verbalize why it's important to think about their beliefs the way Lee Strobel did.
As a professional educator, all I can do is beg that you not ask simplistic questions like, "So, what do you think?" If you'd like more guidance on how to create an appropriate set of essential, thought provoking questions to ask adults or high school youth, please contact me through the comments.
I got the video through Netflix but it's also available at Amazon at a very reasonable price.