20. Marc Maron
In 2009, it looked like Maron's career was circling the drain. A cranky presence who veered between political stuff and open-wound personal drama, Maron, a fixture in the 1990s alt-comedy scene, had never broken big. (He'd had various Air America shows cancelled three times.) Then he launched the twice-weekly interview podcast WTF with Marc Maron from his garage and stumbled into a Travolta-in-Pulp Fiction-type comeback. Originally focusing on fellow comics, but now including everyone from Jakob Dylan to Jon Hamm, Maron's WTF is a must-listen for anyone interested in the art, craft and history of comedy. He blends his own armchair-shrink neediness with a knack for getting his guests to sound awfully relaxed and open, which makes for riveting listening. This stuff should be in the Library of Congress.