I only recently discovered Lex Fridman's podcast (2 monthes ago), but I've been obsessed! The Fiona Hill episode (#335) was great. The climate change discussion between Bjorn Lomborg and Andrew Revkin (#339) was very educational. Ray Kurzweil (#321) was awesome as well. I wonder how that guy (Lex) has time to work his real job since he seems to put out 2 episodes a week and they're all 2-4 hours in length and he clearly does his homework!