Playlists of full lecture series for dozens of courses.

Departments with content here include:
Astronomy
Biomedical Engineering
Chemistry
Classics
Ecology and Evolutionary Biology
Economics
English
History
History of Art
Italian Language and Literature
Molecular, Cellular and Developmental Biology
Music
Philosophy
Physics
Political Science
Psychology
Religious Studies

See also the Open Yale Courses web site, which opens with:

Over 1200 talks (as of Aug 2010) by leaders, experts and visionaries.

Every week, Google brings in a speaker of note for a "lunch time" talk, free and open for all employees to attend. Now with so many Google offices, sometimes there are several speakers per week, and sometimes the same speaker appears over time at different locations.

Most of these talks are excellent. More than food for thought, these often go in-depth into a new technology, new advances, and revolutionary understandings of applications and development of technology and society.