This is an universal comic GM-less rule system. “Yes, But” is a game about always succeeding while failing spectacularly. It is best played with four or more players with a twisted sense of humor.
In many RPGs, a character is defined by his or her strengths. Players try to do something, roll and see if they succeed. In “Yes, But” characters are defined by their weaknesses. YES, you always succeed at your attempted action somehow, BUT the amount of hilarious fallout and weird consequences depends on your ineptitude at given task. The players who come up with most absurd proclamations are rewarded with Thingies, which leads to events quickly spiraling out of control. Whoever earns most thingies by the end of the session, wins!