DEREK: "Do you happen to know what time of year neurosurgeons are busiest, Dr. Stevens?"
IZZIE: "There's a particular time of year?"
DEREK: "There's no hard or fast rule, but brain injuries tend to pile up around the holidays. Folks fall off roofs while they string up lights. They go skating for the first time in a decade and break their heads open. Every year people drive through blizzards to get to parties where they kiss germ infected strangers under poisonous mistletoe. Then they get drunk and smash their heads through their windshield on their way home. But there's no hard or fast rule."