Is it the most famous? I mean there a lot of Christians, but they tend to score pretty low on "knowing what happened in the bible". So you have to find the people who know of the story.
Then people who know the details, like Jesus was betrayed by Judas and was crucified by Rome.
Then people who know even more minute details like how much did "Judas get paid."
I literally had a conversation a week ago with my brother when were he was watching TV and I was shit posting and he asked me about the silver coins reference in some movie.