SPARTAN RACE Obstacle Racing - Spartan Sprint & Super Spartan obstacle course trail races and the Spartan Beast and Death Race endurance race[ http://www.spartanrace.com ]
Spartan Race has an obstacle course challenge for all: These challenges include Marathon 10k/5k, Fun Run, Mud Runs, Super Sprint 5K obstacle/adventure racing, Super Spartan 8+ mile obstacle course and the Spartan Death race - arguably the toughest endurance event on the planet.

Death Race™ Challenge - The Spartan Race | Fun Run[ http://www.youmaydie.com/ ]
Death Race™ Challenge is a 24-hour test of extreme physical and psychological stamina. Warning: This is not an ordinary obstacle/adventure racing, mud runs, Marathon 5k or Marathon 10k, fun run, tough guy! We highly suggest you come to a Death Race Camp before attempting this race.