Recently I've come across some collegiate level education that's free online. This has potential to be pretty beneficial if you're prepping to go to school full time or if you're just looking to get ahead of the curve.
The Educational Portal offers credit for the courses taken upon completion of a proficiency exam. I'm not sure of all the details, but if you're seeking an undergraduate degree, it seems to be a pretty good deal. Or you can always brush up on your Algebra in order to talk trash to your kid's 7th grade teacher.
Educational Portal
MIT also has some stuff. I haven't sifted through much of it, but it looks valuable.
MIT Open Courseware
If anyone knows of more good sources for college level courses, please post away.