The schedule with the live video is here (click).Yes, I took the picture in Harvard's Jefferson J253.
Freeman Dyson has been a genuine peer of folks like Richard Feynman etc. He's known for the Dyson series – some of the most comprehensible derivations of the perturbative expansions in quantum field theory. He's been thinking about biotechnology, space exploration, extraterrestrial life, metaphysics, and many other things in more recent decades.
The talks began three seconds ago i.e. today at 9 am New Jersey Time (3 pm Prague Summer Time). Dijkgraaf will do an introduction and there will be folks like Seiberg, Witten, Yau, Rees, Callan, Drell, and Happer (Dyson's fellow global warming skeptic who will talk about the reasons of the paused global warming). And others.
Incidentally, Google Maps finally added the Street View mode for the LHC collider (new layout here, story here) so you may walk around the 27-kilometer tunnel and check all the detectors from the viewpoint of the Swiss pedestrians who accidentally get lost 100 meters under the sidewalk.