Ok. This is neat. It’s a Java window that shows how fast one infected individual can destroy a population.
Zombie Infection Simulation v2.3
zombies
Living Dead Zombie Rules
Living Dead is a set of free roleplaying rules for the zombie apocalypse.
Unheroic Samurai
Unheroic Samurai is a set of free wargames rules for combat with classical Samurai versus undead horrors.
Zombie Skirmish Rules
Table Top Titans have released Twilight, a set of free miniature wargaming rules for skirmishes in a zombie plagued world.