Grav Armor is the classic Dwarfstar game of future armored warfare. From the site:
GRAV ARMOR is a fast-moving game of future armored warfare for 2 players. It realistically simulates the high-speed, high casualty combat between streaking gravitic vehicles, surface-effects craft, supersonic fighters, orbital dropships and power-suited infantry. The modular map sections allow scenarios to be played on radically different types of planets (earthlike, molten, frozen or airless).
Pondemonium is a free board game of conflict between frogs and turtles.
James Catalano offers Bosconian D, a free solo boardgame based on the classic Namco video game. To find it, you have to scroll down to the bottom of the page, past his (very cool) retro video games downloads.
Dave Ferris offers Napoleon at Chattanooga, a print and play boardgame that simply has to be described by the author himself:
Napoleon at Chattanooga: Boardgame of Napoleon’s famous campaign in the Tennessee Valley, conquest of the Solar System, and an armoured regiment named Bob. Some assembly required. My most successful boardgame design. 420K zipped archive includes maps, counters (must be glued to cardstock and cut out), charts, rulebook, and errata.
The Battle of Ayrene’s Woods is a free print-and-play fantasy board game.