I've updated my 2 year old list of university lecture (MOOC) websites.
Coursera: https://www.coursera.org/
edX: https://www.edx.org/
MIT OpenCourseWare: http://ocw.mit.edu/index.htm
Open Yale: http://oyc.yale.edu/
Harvard Extension: http://www.extension.harvard.edu/courses
iTunes U: http://www.apple.com/education/itunes-u/
Khan Academy: http://www.khanacademy.org/
Wikiviersity: http://en.wikiversity.org/wiki/Wikiversity:Main_Page
425 Free Online Courses: http://www.openculture.com/freeonlinecourses
TVO's Big Ideas: http://bigideas.tvo.org/
CBC Radio's Ideas: http://www.cbc.ca/ideas/episodes/
Last but not least there's the more traditional method of sitting in on a lecture at a near by university.
