First the good news.  When the annual DHI conference was held in Boston, I conducted a 3-hour code class for architects (I later conducted the class for our DHI chapter.).  Public speaking isn't my favorite thing to do, so when one of the attendees approached me before class started and said, "You're not REALLY going to talk for 3 HOURS about CODES, are you?", I got a little nervous.  When we conduct presentations for architects, they're typically lunch-n-learns - 1 hour max, with lunch (and cookies!) as an incentive to attend.  We get great feedback on our lunch presentations, but asking architects to sit through 3 hours of discussion on hardware and codes was a different story.  To my surprise, about 100 architects registered to attend, they actually showed up, and they stayed until the end.  I didn't lose my train of thought, pass out, have an "accident", or lose my voice, so I considered the class a success.