The "Murph" workout is a popular CrossFit challenge named after Navy Lieutenant Michael Murphy, who was killed in action in 2005. It is typically performed on Memorial Day to honor fallen soldiers. The workout consists of a one-mile run, followed by 100 pull-ups, 200 push-ups, and 300 air squats, finishing with another one-mile run. Participants often wear a weighted vest or body armor to increase the intensity. The workout is designed to test endurance, strength, and mental toughness, making it a significant event in the CrossFit community and a tribute to those who have served in the military.