I play Traveller - "Science-Fiction Adventure in the Far Future" -- 5626 A.D, to be exact.
My sig line gives my personal stats in Traveller terms (except for AQ, of course).
I've adapted Traveller rules to play Stargate: SG1, Star Trek, and Star Wars.
There are other adaptations that allow RP'ing in either the Roman Republic or Imperial Rome.
It has an extensive set of Commerce and Trade rules.
Every die roll uses D6 only -- roll 2D for 8+ to hit in melee combat (dice modifiers for STR, DEX, range, and other battlefield variables).
21 "Hit Points" are average for every character. There are no reincarnation or resurrection saves - once your character is dead, it's dead. This encourages tactical play over machismo.
My games are set in the Spinward Marches, a frontier sector bounded by Vargr, Zhodani, Sword Worlders, Darrians, Aslan, and a few other species that the players haven't met yet.
Marc W. Miller is my hero.
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The previous signature line has been cancelled.