Quatar said: I'm looking for a system that's relatively light on the rules department, using a big portion of common sense or Rule of Cool instead of micromanaging everything with fifteen thousand tables and focuses more on the Roleplaying aspect of RPGs vs Rollplaying. I can think of no game that better internalizes the "Rule of Cool" and a lack of micromanagement than Risus . It's a d6-based, freewheeling light system that puts the characters front and center. There aren't any rules you'd have to change to allow a sci fi game, but there isn't any explicit support for it either. Risus itself is free and weighs in at a trim 4 pages these days, but the ten dollar Risus Companion - which you don't need to play, honest! - is worth every penny. It's the best general purpose GM guide and advice book there is and also explains the tao of Risus in a way that takes it from amazing to transcendentally great. That being said, it is hard to beat the venerable D6 suite of systems and it's really the poster child for space fantasy. What rules there are don't get in the way and rolling handfuls of dice is always fun. I'd go with MiniSix over D6 Space, personally, because its cleaner and presented better and gives you more room to tack on what you want into the game. Tracking down a print copy of any of the versions of the West End Games Star Wars core books would be my second choice; from experience, it's pretty easy to strip out the Star Wars and put what ever you want.