Strange Aeons is a skirmish wargame of Lovecraftian horror. You can get a Strange Aeons demo kit here, and the quick reference sheet for the second edition Strange Aeons here.
skirmish
Scavenger Skirmish Survive
Scavenge Skirmish Survive is a set of free wargames rules for a tabletop game set in a post-apocalyptic volcanic winter. Link goes directly to a pdf
1 Page Napoleonic Skirmish
The Jackson Gamers have these free wargames rules for Napoleonic skirmishes. The best part: the rules are just one page long.
Ares Fantasy Skirmish Demo rules
Majestic 12 games offers these demo rules for their Ares fantasy skirmish miniature wargames system. They explain:
ARES: Miniatures Wargaming System is a complete skirmish-level fantasy game. But it is also much more. The flexibility of the system allows players to use any wargaming miniatures in their collection. Over two dozen sample figures are detailed in this book, but the real strength of ARES is its figure creation system, that encourages players to use their imaginations — which is the way it should be! Also included is a fully-customizable magic system, providing players with the opportunity to design their own spells for their troops.
Rules By Ral variant
The Jackson Gamers present their Medieval version of the venerable Rules by Ral.