MIT Open Courseware - Free Course Materials

A friend pointed me to the MIT Open Courseware site: This site offers the full cirricula for a huge number of MIT courses.

I've always found that when I'm interested in deeply learning something new, my biggest roadblock is knowing where to start and determining what's relevant. I haven't looked too closely at what material is actually offered on this site, but at the very least the full reading and assignment/project list for each course is described in detail, giving ample direction for getting started on a topic.