Because of my background in physics, and I was invited to speak with both classes about the perspective of modern science on the fundamental nature of the world. We discussed some challenging fields in modern physics, including quantum mechanics (and what it says about fundamental particles, the greek atoma) and general relativity (and what it says about space, the greek void).
Skype video-chatting allows for a lot of interaction between the people on each end, and despite the fact that I was participating from home, with the IPS discussion taking place during our fall break, connection speed was never a problem. Voices were sometimes hard to hear on the other end, so some investment in audio hardware would certainly be worthwhile where a group is participating.
Despite the challenges both conceptual and technological, both classes were very successful. For more than an hour, we discussed some very difficult ideas in modern physics. The questions students from both schools posed to me and to each other, and the responses they gave, showed an ability to think creatively and critically. Maybe even more exciting, I understand that for many students, these discussions continued well after the class was over!