I loved 'Classical Sociological Theory'. It introduces the ideas of 8 'sociological' thinkers from Bernard Mandeville to Norbert Elias. The course uses the medium of a MOOC by providing insightful pictures and the course references interesting source material.
I must confess I always find it quite hard to take psychology very serious, but this course does a good job at cutting to the bone of what psychology is about and refrains from making unfalsifiable statements.
EDIT:
Almost forgot Astronomy: Exploring time and space: https://www.coursera.org/learn/astro. It comes with a very awesome free online book/website.