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."
Leonard Susskind has published a bunch of videos outlining the theoretical foundations of modern physics. The collective title is Modern Physics: The Theoretical Minimum, and it seems intended to serve as his take on the simple physics of everything. He disregards constants in the equations, using the natural units wherever possible and so on, thereby managing to explain the dynamics of a wide range of physical phenomena quite compactly. The series on cosmology was excellent.