Dogfight WWI Air Combat Rules

Dogfight! is a set of free wargames rules from Don Gelwwe. The rules have a bit of a different flavor from most of the genre. Don writes:

These rules are an attempt to create for players a different experience in gaming WW1 aerial combat. They are meant to confront players with broader tactical decisions that reach beyond the immediate specific-maneuver-choices of a moment within a battle to deal with what is (or will be) happening within the scope of the engagement as a whole. The demands placed on players emphasize these larger decision-making aspects of a pilot’s energies rather than the common, traditional focus on flying of most other rules. By removing the need for the player to micro-manage the piloting of the aircraft (these rules assume that the little fellow in the model already knows how to do that…), gametime can be devoted to deciding what to do rather than how. Instead of choosing which specific maneuver to use to position one’s aircraft in a particular way, players will choose amongst tactical objectives (such as “attack that enemy” or “be over there”) and then decide on the risk-level undertaken to achieve that goal. The success of an effort (attack, defense, movement, observation, etc…) is determined by dice rolls that are influenced by the pilot / aircraft quality as well as the level of risk (which reflects the difficulty of the task attempted).

You also can discuss the rules in the forums here.

Warzone Modern Battles

Warzone Modern battles is a set of free modern Wargaming rules for 1:72 or 20mm Squad/Platoon games.

Fast Play Medieval Skirmish Rules

Fast Play Medieval Skirmish Rules are

designed for fairly large-scale skirmishes; up to about 80 men a player. They will do for many periods or settings, so long as troops can be classed into three distinct broad categories of quality. The rules emphasise the importance of sticking together for mutual protection and the value of weapons with longer reach: spearmen can fight in two ranks, pikemen in three. Men in the second rank with javelins can support.
The rules recognise two ways in which figures may be combined, Contingents and Groups. Contingents are real units (e.g. a Contingent of 15 archers from Berwick under their bill-armed vintnar) and are used for organisational and morale purposes in these rules. A good size for a contingent is 32 points. Groups are temporary (sometimes fleeting) arrangements of men occurring in combat situations. Hand-to-hand combat is fought between Groups (which may be as small as one man each) and casualties occur almost at random within the Group

Also, an add-on for leaders and dueling.

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Border Reiver is a set of miniatures rules for playing medieval and renaissance era games in the border regions between England and Scotland.

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Viking Raid is a set of free wargames rules for carrying out a competitive Viking raid. The set uses playing cards as an integral mechanism.