If this were my presentation, I'd start it out with an object lesson, by making them very, very uncomfortable. Because a gifted individual is just as different from a normal one as the normal one is to one with mental disabilities, I'd begin my presentation by lecturing to them as if they were all disabled. Once they've all begun to get frustrated and tuned out, I'd snap their attention back (dropping something heavy is pretty effective) and then let them know that the last five minutes of their lives is like what an unchallenged gifted child experiences for every moment of their school day.
Open discussion for the next several minutes, looking for responses from the audience as to how they felt and how they wanted to react which are commonly observed in gifted kids.
