Check out Open-Video.org!
The content includes 30-60 minute movies from the early 1900s (including silent films!), almost 500 documentaries from NASA, the Digital Himalaya Project from the 1930s, advertisements from the 1950s, CHI materials from the Ass'n for Computing Machinery, and television PSAs for reproductive health in Yemen.
There are some great educational videos appropriate for use in schools, especially in the sciences. There are a handful of entries on the word "brain", and many animated films.
The search is very good -- you can limit to color, b&w, by length, and silent or with sound. The majority of these images are either in the public domain or otherwise available for educational use, but check the Copyright Statement for more information.
Warning: you may spend a lot of time at this site!