Disclaimer: Other dudes thought of this stuff. D. V. Baker's In A Wicked Age gives use the owe list, and the basis for the dice method comes from a thought on a Story Games thread.
So, here's the basic idea.
Roll some dice. You pick the size. Bigger size is bigger risk, but better chance of narration.
Ah, ah, ah. Let me explain, folks.
Whoever rolls the highest narrates the scene however they like, except they shouldn't be too much of a jerk and they need to remember who won what.
Whoever gets a prime number succeeds on their action. If opposed actions both get successes here, higher number takes the cake with lower getting a lesser success.
D4 - 1,2,3
D6 - 1,2,3,5
D8 - 1,2,3,5,7
D10 - 1,2,3,5,7
D12 - 1,2,3,5,7,11
D20 - 1,2,3,5,7,11,13,17,19
If you neither get a success nor narration, put your name on the owe list.
You can do some stuff with the owe list. I need to work on how this game works, more.