I've been a fan of Ricky Gervais for a couple of years now, and came across his podcasts on iTunes. I bought the first series on a whim and the following weeks have had it playing wherever I go.
It features Ricky, Stephen Merchant and a previously unknown Karl Pilkington. Karl actually seems to dominate the show because of his stupid/genius comments (you'll understand when you hear it) that always garuantee to be hilarious, his strange views and outlooks on life that have been compared by Ricky to a fifty year old man and his repore with the other two who prompt, question and just make fun of him.
Depending on what series you have the podcast will have features such as monkey news - where Karl tells some very funny story (usually totally ridiculous!) featuring a monkey, Rockbusters which is basically like Blockbusters which is equally as funny and generally any funny story that Ricky or Stephen have.
If your a fan of Gervais definately get this or any of his podcast related stuff, if you're not familiar with his work get it anyway just for Karl Pilkington.