I heard about this event on an interesting BBC broadcast yesterday.
Convict Poker - Four inmate cowboys sit at a table in the middle of the arena playing a friendly game of poker. Suddenly, a wild bull is released with the sole purpose of unseating the poker players. The last man remaining seated is the winner.There is more about the prison rodeo at the Wikipedia link, and other videos posted at YouTube. The movie highlighted in this video is not at my library, but I bet it would be fascinating.