Stephen Wolfram and George Johnson on ‘A New Kind Of Science’ (ie. on automata and computation.)
Anthony Aguirre and Clifford Johnson chit chat about string theory vs. field theories, coupled with some cosmology.
Sean Carroll and Mark Trodden from Cosmic Variance blog on the topic of cosmology, dark energy and other interesting issues.
Peter Woit and Sabine Hossenfelder on various sociological issues concerning young theoretical physicists.