Wall Sprints- 2 min of sprinting wall to wall, 30 sec of push ups, 2 more minutes of sprints, 30 sec of pull ups, 2 more minutes of sprints, 30 sec of squat jumps, then overtime.
close second would be grind matches. Never did them in high school when the room was warm. But All Navy coach Rob Hermann had us doing them in that wide open gym in Pensacola. February in Florida is freakin cold. You never quite warm up. The mat feels like an ice cube. You scramble like a mad man trying to avoid letting skin touch the mat for any length of time.