Yeah, I saw that - it was very cool. For those who missed it, they tossed a 300 tow rope (i think it was that long) behind the cruise ship and let it drag before even entering the water. They then passed the cruise ship in a normal ski boat. The mythbuster entered the water, and began to wake board from the ski boat. They moved closer and closer to the rope dragging from the cruise ship, and he then had to make the transition from the ski boat to the rope being dragged by the cruise ship. He fell once, and they had to hurry up, pass the cruise ship, and try again. He managed it on the second attempt, and stayed up for what seemed to be a few minutes.
RCCL - Adventure OTS (Honeymoon!)
CCL - Carnival Miracle
RCCL - Enchantment OTS