Boards
Academic Earth - lectures from Yale, Harvard, etc for free
Now you can get an Ivy League education for nothing. Well, apart from all of the tutorials, face to face interaction, essays, grading, assessments, projects, library access and sweet sweet loving.
Lots of cool lectures about lots of things, well worth a look if you have time to kill and want to learn about stuff. You don't even have to take notes! Pretty nifty.