Grand Fleets demo rules

Majestic 12 games has these demo rules for their Grand Fleets miniature wargame. My group has played these and really enjoys them. Majestic 12 explains:

Grand Fleets is a comprehensive miniatures game of dreadnought-era naval warfare. In addition to rules for everything from ships to aeroplanes, Zeppelins to submarines, the rulebook includes:
Data cards for over 120 ships, plus guidelines for converting any ship of the period to game values; Eight scenarios encompassing conflicts from the Sino-Japanese War of 1894 through the opening salvoes of World War Two, including several variants; Fifteen pages of weapon data, covering all major gun and torpedo models in use through 1939, over 200 aeroplanes, and more than 20 airships; and Optional rules for flotillas, night-fighting, smokescreens, and more!

15mm War Galleys

Here are a set of instructions for building 15mm models of ancient War Galleys from the Jackson Gamers.

ECW Rules

The Jackson Gamers have this set of free wargamesrules for the English Civil War. They use a card activation system, (not surprising, considering the acknowledged Brom influence), and d6s to resolve actions. These rules are 20 years old and in their 6th edition, so they are well-tested.

For The Masses demo rules

Majestic 12 Games has these demo rules for their For the Masses Fantasy miniature wargames system. Here’s their blurb:

For The Masses is a complete fantasy mass-combat wargame system. But it is also much more: The flexibility of the system allows players to use any fantasy setting and armies to play out famous fantastical scenarios and ancient epic battles. Several sample army lists are included in the book but the real strength of For the Masses is the unit creation system. This system encourages players to be creative, use their imagination and have fun, which is the way wargaming should be.

100 Years War Rules

Here is a simple, two page (front and back) set of rules for the 100 Years War by Eric Wood.