Two good ones I've discovered recently that I haven't seen mentioned here:
1. The Dollop w Dave Anthony and Gareth Reynolds- one comedian researches a strange-but-true historical tale and tells it to another comedian, who doesn't know what's coming Some examples:
Hetty Green, the Witch of Wall Street and
Fed Ex Flight 705. If you liked that thread we had going here about crazy Wikipedia entries, this one's for you.
2. The Great Debates: Two comedians (often joined by guests) debate yes/no or pro/con of various things. Some recent examples: "William Shakespeare saw a black woman naked," "The weatherman has the easiest job on a news team," "it would help Hillary Clinton if her email contained a draft of erotic Big Bang Theory fan fiction." This would also be a good idea for a FFA thread, now that I think about it.