Somewhere around here I have a copy of a video of a talk by him in front of a large audience, I think at a MathFest session, speaking on "The Many Lives of Binomial Coefficients." I never listened to the whole thing because the audio quality is very bad. It's bad because someone put the microphone among the audience rather than with Rota, so that every time the audience reacts to something it drowns out what Rota was saying.