Last year I discovered the Radiolab podcast and really enjoyed listening back to all their past episodes and each new one as they were released. It's a fascinating podcast that covers all kinds of interesting stuff in accessible and entertaining fashion. I thoroughly recommend it!
I particularly enjoyed this one about recent discoveries in the world of fungi that has revealed new understanding of tiny networks that connect whole groups of trees. If you've a spare half hour then click play, I can pretty much guarantee you won't regret it!