For Continuing Education, these guys are a pretty good deal.

I wonder if this link will work for general use, it's a transcript of an introductory lecture on DesCartes...part of it, anyway.

These guys sell audio and video courses from eminent university professors.

I want this one, Joy of Thinking: The Beauty and Power of Classical Mathematical Ideas.

I bought

Argumentation: The Study of Effective Reasoning(24 lectures, 30 minutes/lecture)
Course No. 499

Taught by David Zarefsky
Northwestern University
Ph.D., Northwestern University

I've listened to 6 lectures so far. Pretty good stuff. Lost track of the study guide. I think it fell behind the coffee table.