Not only are dice considered contraband, but dice substitutes like chits may also be confiscated. The only places you'll find dice in most prisons is in access-controlled lounges and the like.
Cards follow a similar prohibition.
However, shooting rock-paper-scissors would be effective (and impossible to confiscate) for adjudicating successes or failures.
HP = Cigarettes or toothpicks or sticks of gum.
For a ruleset, you'd want something ultra simple, like the good old Metagames The Fantasy Trip: In The Labyrinth.