The only documentary about Grigori Perelman has recently got English subtitles. (Perelman is the guy who proved the Poincare conjecture and then refused a million dollar prize.) It is for laymen, and very dramatic.
http://www.youtube.com/watch?v=Ng1W2KUHI2shttps://www.youtube.com/watch?v=Ng1W2KUHI2s