In addition to adding another vote for Serial...

The Art of Manliness (varies)
Mad Dogs and Englishmen (politics)
Ace of Spades podcast (politics)
NPR Intelligence Squared (varies)

Barbell Shrugged (fitness/weightlifting)
Jay Ferrruggia Show (lifting and men's lifestyle, but he veers into philosophy, which is interesting)

The Loopcast (national security/terrorism)
Lawfare (legal side of national security)

Just found Philosophize This, which examines major philosophers and their ideas chronologically through history (starts pre-Socratic and he's up to David Hume) as well as specific topics like slavery. Really intrigued.