Why do we need the Book of Mormon?", but it would also make a great FHE activity for older kids. The focus of our lesson was that by reading the Book of Mormon, we can find answers to gospel questions, find comfort, and draw nearer to Christ. I used a lot of the ideas from this site to teach.
This was meant to be a sort of "homework" assignment, which if they filled out and sent me a picture of completed, I would bring them a small treat the next week. I don't usually like to resort to bribery like that, but I felt that the exercise of learning to find answers in the scriptures was valuable enough that I wanted to give them a little extra incentive to do it.