Simplis Medieval Miniaturus is a set of free wargames rules for miniatures battles set in medieval times.
Terrain Thralls has an illustrated tutorial on making a half-timbered, two story roadhouse. The end result is beautiful, and would be useful in a wide variety of settings.
The Krigsspil site has a huge number of medieval and renaissance flags available for downloading.
Simplus Medieval Miniaturis Rules (SMR) is set of free wargames rules for battles in the medieval era.
To Cry A Joust is a set of free wargames rules for jousting combats.