The OpenCourseWare consortium is a group of Universities who provide the courseware (e.g. lecture materials, PowerPoint presentations, audio/video clips, and so on) for certain courses for free, in order to advance the pursuit of knowledge.
Browsing through the University list it’s quite obvious there are plenty of options to look for material.
Visiting UC Berkeley’s website, we see courses ranging from Biology to Statistics to Religious Studies are available. Similar offerings can be found at one of the nearly 60 Universities participating, in a variety of languages.
Of course this material has more uses than just for a student looking for non-credit learning. A teacher looking to prepare a new course or a University student looking to brush up on his knowledge can equally benefit from the available information.