Acies is a very nice looking two player card game designed to simulate conflict between ancient armies. it looks like it would be a fun thing to play on off-nights when your regular miniatures games end early. All the parts you need are there to download and print out.
ancients
De Bellis Armatis
De Bellis Armatis is a set of free wargames rules for ancient warfare.
Corvus Ancient Naval Rules
Corvus is a set of free wargames rules for fighting ancient sea battles.
Trireme Ancient Naval Rules
Trireme, from Andy Watkins, is a set of free naval wargames rules. These are of the one-page variety, which means that there is much to recommend them. I also like the staggered movement system based on boat speed, which reminds me of the old Car Wars system.
Free Black Powder, Hail Caesar and Pike & Shotte Rules
For a limited time, Warlord Games is offering free digital copies of Black Powder, Hail Caesar and Pike & Shotte