Chevauchee is a set of free wargames rules for man-to-man combat during the 100 Years War.
The Illinois Historic Preservation Agency has a great collection of paper models of historic Illinois buildings. You can put together a very nice early 20th century mid-western town from these models.
Comic Book Plus has a huge selection of Pulp Aviation Comics, including such gemas as Captain Aero.
Apostolos is a print-and-play board game in which you build churches, guard them against false teachings, deal with persecution, and raise up more workers to make more churches. For 2 - 4 players.
SMART stands for Simple Miniature Adventure Rules and Tactics. They're a set of free wargames rules for fantasy and medieval gaming.