FUDGE

FUDGE is a free universal roleplaying system designed for freeform play. There is a seven-point scale of possible results for every action, and points on the skill are named from Terrible to Superb. You rate your character's skills according to where they start on that scale. Then you roll four Fudge dice. These are labeled [+][+][ ][ ][-][-]. Each [+] raises the result by one point, and each [-] lowers it by one. Now you're probably at a different point on the scale, and that point describes how good the results are. So the GM interprets what that means.

Just about everything else in the game is optional. You can pick skills from a list, or you could make them up yourself. You can give the characters fundamental stats that influence all their skills in some area, or you could just rate all their skills individually.

FUDGE is the basis for the FATE system.