STaRS: The Simple Tabletop Roleplaying System

From the introduction:

More than anything else, STaRS strives for simplicity. If you can't be playing within thirty minutes of finishing this book, we've done something wrong. The rules are simple as we could make them, so that you can play without constantly referencing these rules. They're written to enable rather than constrain you, so you can spend more time having fun and less time flipping through rule books.

The game is easy on Directors as well as players. Creating non-player characters is a breeze — no need to spend hours crunching numbers and looking up abilities to create an enemy who'll only appear once.