I knoooow. I've just seen my own fair share of open canon taverns. But, few had rule sets, it was just hangin' out and rping. And it was sooooo prone to people showing up and being like "Ah ha, so I'm a trickster god and anything you do, I'll just nope it because I don't understand Improv"
So, having a rule set designed around just allowing success will help anything be possible for anyone!
In this system, you roll a number of d6 based on if you are good or bad at it. (Advantage 3d6, Neutral 2d6, Disadvantage 1d6)
And, if any of them land on 5 or higher, you do what you wanted to do and get to describe it!
So, it lets you do as absurd things or as simple things as you want!
Kinda reminds me of regular show where an Immortal yeti man is EXACTLY AS USEFUL as a slacker who plays video games purely in the situation itself.