We've discussed how to audit a local university course, and we've talked about the outstanding audio courses available from the Teaching Company. Here's yet another option for taking that class you regret skipping in college: free course materials from the Massachusetts Institute of Technology.
MIT has posted more than 1,800 classes to its Open Courseware system. You can review lecture notes, watch video or listen to audio of lectures, and even test yourself with actual exams. It's the most convenient and least expensive way I can think of to learn something new.
It's no surprise that the site's most popular classes are things like "Linear Algebra" and "Introduction to Algorithms." (I'm really more in the market for a class like "How to Add Without a Calculator.") For the rest of us, classes are available in about three dozen departments, including architecture, philosophy, literature, music and writing.