Sturgill Simpson is an American country music singer-songwriter. His new album "A Sailor's Guide to Earth" comes out on April 15, 2016. http://sturgillsimpson.com

Adam Cropp is an Expedition Leader on the National Geographic Orion, from the remote jungles of Papua New Guinea to the frosty frontiers of Antarctica and everywhere in between.

Brendan Schaub is a mixed martial artist and also a former college & pro football player. Bryan Callen is an actor and stand-up comedian. Together they host "The Fighter & The Kid" podcast available on iTunes.

Greg Fitzsimmons is a stand-up comedian. He also hosts his own podcast "FitzDog Radio" available on iTunes.

Dan Auerbach is a musician and record producer best known as the guitarist and vocalist for The Black Keys. http://podcasts.joerogan.net

John Dudley is a pro archer and host of "Nock On TV." Check out his podcast "Nock On" available on iTunes. https://www.youtube.com/nockonarchery

Gad Saad is Professor of Marketing & Concordia University Research Chair in Evolutionary Behavioral Sciences and Darwinian Consumption and author of "The Evolutionary Bases of Consumption" and "The Consuming Instinct" "The Saad Truth" on Y...

Ari Shaffir is a stand-up comedian and also hosts the podcasts Ari Shaffir’s Skeptic Tank & Punch Drunk Sports. Check out the 2nd season of his show This Is Not Happening on Comedy Central. http://arithegreat.com

Kevin Rose is an Internet entrepreneur who co-founded Revision3, Digg, Pownce, and Milk. He also served as production assistant and co-host at TechTV's The Screen Savers.

Brendan Schaub is a mixed martial artist and also a former college & pro football player. He also hosts a podcast with Bryan Callen called "The Fighter & The Kid" available on iTunes.

Michael Shermer is a science writer, historian of science, founder of The Skeptics Society, and Editor in Chief of its magazine Skeptic, which is largely devoted to investigating pseudoscientific and supernatural claims.

Tovar Cerulli is a "vegan-turned-hunter",environmentalist and author . His book The Mindful Carnivore is available via Amazon. http://tovarcerulli.com/

Duncan Trussell is a stand-up comedian, and host of his own podcast “The Duncan Trussell Family Hour”. http://podcasts.joerogan.net http://duncantrussell.com

Eddie Bravo is a jiujitsu black belt, music producer, and author. http://www.eddiebravoinvitational.com/

Alison Rosen is a podcaster, writer, and television personality. She also hosts her own podcast called "Alison Rosen Is Your New Best Friend" available for download via iTunes.