I think my favourite moment was when my friends and I were playing Infection on Halo 3. Three of us had gotten into a Warthog and started driving and circles around the map, and we managed to kill our other friend who was the zombie several times. We started to taunt him. And then when one of my friends yelled "Man, Do you even Halo?!" the Warthog suddenly exploded, and killed us all. Our friend had snuck up on us. We laughed for minutes straight, and it still remains one of our most memorable Halo moments...