Large Scale Civil War Battles is a set of free wargames rules where one base=1000 men and an inch=100 yards.
Atomic Comics and Stories
Comic Book Plus has a collection of “Atomic Comics” from the late 1940s through the 1950s that attempted to capitalize on the public’s fascination with atomic energy.
Dungeons and Dragons Paper Model Buildings
Many moons ago, TSR / Wizards of the Coast released a series of paper buildings for use in D&D games. They’re now available free for the downloading. Any medieval / fantasy wargamer will find these useful. I think they’ve really stood the test of time.
Inquisitor Rules 40k Universe
Inquisitor was game produced by Games Workshop set in the Warhammer 40K Universe. Curiously, it used 54mm figures.
The game is out of print, but a rules archive is at the link.
Texturing Gaming Board With Spackle
This video shows a nice technique for texturing game boards with filler (spackle).