I have recently discovered two sites that let you take college courses free. Well, you're not really in it, but it's essentially the same thing; you just don't get any credit. There are some interesting courses and quite a bit to learn, even if the courses are basic, or only part of them are offered.
This site essentially lets you take MIT courses for free. They have videos of lectures and tell you everything happening in the class(assignments, suggested readings, etc.). I didn't count but it says it offers 1800 courses. The only problem I found with the site is that it is somewhat confusing at first to figure out. http://ocw.mit.edu/OcwWeb/web/home/home/index.htm
This website is similar but from what I've seen the courses are more in depth than the MIT ones, although they are more basic courses. Also there are less courses offered for free.http://webcast.berkeley.edu/index.php