 O'Brien's senior thesis concerned the use of children as symbols in the works of William Faulkner and Flannery O'Connor.During college, O'Brien briefly played drums in a band called the Bad Clams, was a writer for the "Harvard Lampoon" humor magazine, and developed a spoof of the video game "" in which the Boston Celtics play against a classical ballet troupe.During his sophomore and junior years, he served as the "Lampoon"'s president.