Every year, the Gettysburg Foundation hosts a series of speakers on Gettysburg. They put up a big tent behind the Visitors Center and lots of chairs. I was surprised to see so many of them occupied when I gave my talk, because it was at the end of the day (July 6, 2013). It is a free event and is coming up again this year.
To see me talk about the best and worst generals of Gettysburg, check out this link: http://vimeo.com/72363918. Go to my Resources link to see the entire list of speakers and their videos.
I will add my list of the best and worst generals here in a couple of days.