With a busy schedule and very limited time, listening to a Japanese podcast in the car on the way to and from work is one of the few things I can do consistently to keep up my Japanese ability and learn new words.
Ecclemon was nice enough to recommend the podcast 夢夢 engine (http://www.tbsradio.jp/yumeyume/) and I’ve been addicted to it ever since.
In Japan, the academic world is divided into 理系 (rikei) and 文系 (bunkei). 理系 focuses on studying the natural world and 文系 studying people and the works created by them. In English, these terms map fairly nicely to “the sciences” and “the arts”.
Yume yume Engine is a podcast designed to showcase interesting and appealing parts of science (理系) to students of both disciplines. Each segment lasts around ~30 minutes, and contains an interview with a prominent researcher in some field of science. There is a wide range of fields: robotics, statistics, math, archaeology, plants, medicine, etc.
This show is perfect for adding more intellectual or academic words to your lexicon, as those interviewed usually don’t hold back with using difficult or rare scientific terms (bet you didn’t know the word 病原微生物). Also, if your Japanese is good enough to understand much of the content, you’ll be impressed with how they manage to find everyday, accessible ways to explain different scientific concepts and to really make you want to learn more about this stuff.
Besides the difficulty level, the only other drawback to this show is the multiple advertisements you are forced to hear each time (by Tokyo Electron, the show’s sponsor).
The website contains log of all episodes for easy download (check here) with brief descriptions of each, so try finding one that suits your interest and taking a listen.