The Perimeter Institute has videos of classes of all of their areas of research:

http://www.perimeterinstitute.ca/en/Outreach/What_We_Research/Quantum_Gravity/

http://www.perimeterinstitute.ca/en/Outreach/What_We_Research/Superstring_Theory_/

http://www.perimeterinstitute.ca/en/Outreach/What_We_Research/Quantum_Foundations_/

http://www.perimeterinstitute.ca/en/Outreach/What_We_Research/Cosmology_%26_Gravitation/

http://www.perimeterinstitute.ca/en/Outreach/What_We_Research/Particle_Physics_/

http://www.perimeterinstitute.ca/en/Outreach/What_We_Research/Quantum_Information/

Scroll to the bottom for the lectures.

A lecture from 2005  by Roger Penrose on the pre-Big Bang and Weyl Curvature.

INI Web Seminars: Penrose, 2005-11-07

This one is quite good. "Time is nothing to a photon."