Numberphile

Numberphile's format is almost defiantly simple: point a camera at a mathematician, hand them a marker and a sheet of brown paper, and let them explain why a number is interesting. Brady Haran's interviews — many filmed with University of Nottingham faculty — turn unsolved problems and obscure number theory into something like campfire storytelling. It rewards patience more than CrashCourse does, but the payoff is a real sense of what mathematicians actually find beautiful.