Traveller has it. Cepheus has it. Most of my games have it, too:
The target 8 rule: to do anything, roll 2d6, add positive modifiers, subtract negative modifiers, try to get 8 or more.
So, all you really, really need to play is a character:
- give him a name and three details about his appearance
- give him a nice weapon or tool/armor, or both
- give him an interesting item
- describe his experience
So, Chud from Two-Trees-At-The-River is a gap-toothed, slack-jawed bald man wearing leather armor and a rusty zweihänder. Chud used to be a blacksmith.
Just recently, he left his village because he heard about a great treasure hidden somewhere under the Whitepeak mountains.
On his way, Chud is ambushed by four stinking orcs.
Chud has the armor and the zweihänder, so that’s +2. He’s also really strong, that’s another +1. He has no experience in fighting, however, and there are four orcs attacking him, so I’d say a total negative modifier of 4.
Chud’s player rolls 2d6 and subtracts 1 from each roll. A 4. The referee narrates how three orcs land solid hits, cutting and slicing and stabbing Chud, leaving him badly wounded, but still standing.
Chud’s next roll is a 9 -1, so he is successful. With wild zornhaue, he mows down three orcs… and the last one flees, in shock.