Crash Course. Crash Course offers a course on World History and a course on Biology. They are now up to 15 videos in each course. The videos are fast-paced ten to twelve minute overviews of major concepts and themes. One of the latest World History videos is The Dark Ages... How Dark Were They, Really? I've embedded that video below.
Applications for Education
The fast pace of the Crash Course videos makes them better suited to being reviews or introductions to topics rather than a replacement for lectures and documentary videos.