Yashima is a print-and-play combat game that combines “the speed and complexity of card games with the tactical movement and terrain found in miniatures game.”
Miniatures Rules
Fast Play WWII Aerial Combat Rules
Matt Fritz offers a set of fast play miniatures rules for World War II Aerial Combat.
GrimDark Future Rules v. 2.3
The folk at One Page Rules have released a new edition of GrimDark Future, a set of one-page rules (with lots of pages of armies you can also download)
Battle of Salamis Rules
Matt Fritz offers a simple set of rules for recreating the 450 BC naval battle of Salamis between the Greeks and the Persians. The site even has links to paper models that you can use to play the game.
And All For One Three Musketeers Miniatures Rules
Eureka Miniatures offers And All For One, a set of free miniatures rules for playing swashbuckling miniatures games such as the Three Musketeers. The four page rules set is done in an interesting flow-chart style, making it very easy to follow.