Consortium Games offers Minifigz, a two page rules set for battles with Lego minifigs, and similar mini people. I’m going to have to give this a try.
Update: The original link is dead. You can still find Minifigz on the Wayback Machine.
Miniatures Rules
Crouching Hero Hidden Daggers
Jim Wallman presents yet another game in Crouching Heroes, Hidden Daggers: A fantasy skirmish based on the more fantastical type of chinese martial arts movie. With characters inspired by the Water Margin. Simple rules, with action cards
1-48 Combat WWII Skirmish Rules
1-48 Combat is a set of free wargames rules for WWII skirmish, designed for two players commanding a single squad.
Wars of the Roses Skirmish Rules
The Cool Guy or Dweeb site offers a set of Wars of the Roses skirmish rules.
Away Boarders War of 1812 Great Lakes Naval Rules
Away Boarders is a neat little game for a little-considered theatre of war: The Great Lakes in the late 18th and early 19th centuries. The author also includes some nice 2-D paper models of the ships, as well as counters.