I just ran across In Our Time, a great series from BBC radio exploring science, philosophy and culture. Each program focuses on a different topic--representations of Hell through the ages, or frothy brain-teasers such as "Does Time Exist?" with discussion by a panel of experts.
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I spent a good portion of the morning sampling various bits and pieces--it's definitely time to haul out the iPod and load these. They'll be great to listen to while driving to work. Or as discussion starters in class.