Those of you who came of age in the postwar era probably have a soft spot for those 16 mm educational/health/training/industrial films of your youth.
Here are two AMAZING archives for this stuff. You can watch stuff online, and you can also download higher rez versions (on Prelinger, at least):
http://www.archive.org/details/prelinger
and
http://www.avgeeks.com/
You can search by topic.
For example, here is part 1 of "American Look," perhaps the greatest film ever about mid-century design:
http://www.archive.org/details/American1958
Parts 2 and 3 are there too.
These sites are addictive. Proceed with caution.