As far as TAL goes, the weightlifting snowman story was really funny. And the Captain Morgan man's story. But I've found myself deleting the podcasts. TAL is good if I'm driving, but if I have an iPod, I have lots more interesting stuff to listen to.
I find Radio Lab really annoying. They have some kind of interesting story going on and then they interrupt it with silly sound effects and inane banter. And I don't like the deliberately naive jive.
BBC's In Our Time, however, is consistently the second-most interesting radio show around. Plus, there are some podcasts of old-timey mystery and science fiction shows that are fun.