Here’s a paper model of a medieval watchtower in 1:140 scale. The site is in German and the babelfish that I used wasn’t very good in translating it, so I can’t tell you much more. 1:140 scale is probably not good for most miniature wargames, but you could easily scale them up when you print.
A two story, half-timbered inn would be a great addition to any wargames table, and useful in miniatures games ranging from fantasy to World War II. It’d also be a lot of fun to work out a rold playing baroom brawl. Here’s a pictorial tutorial on how to do it. A warning, though, the pictures are HUGE and take a bit of time to download.
Brian Cameron’s Warfare in Western Europe is a set of free wargames rules for medieval warfare. The scale is 1:50 and the set leans more toward the “beer and pretzels” style of game, as its just three pages long. But that’s a good thing!
Here is a simple, two page (front and back) set of rules for the 100 Years War by Eric Wood.
The Jackson Gamers present their Medieval version of the venerable Rules by Ral.