<P> O'Brien, like many SNL writers, occasionally appeared as an extra in sketches; his most notable appearance was as a doorman in a sketch in which Tom Hanks was inducted into the SNL "Five - Timers Club" for hosting his fifth episode . O'Brien returned to host the show in 2001 during its 26th season . O'Brien and Robert Smigel wrote the television pilot for Lookwell starring Adam West, which aired on NBC in 1991 . The pilot never went to series, but it became a cult hit . It was later screened at The Other Network, a festival of unaired TV pilots produced by Un-Cabaret; it featured an extended interview with O'Brien and was rerun in 2002 on the Trio network . </P> <P> Things changed for O'Brien in 1991, when in quick succession, an engagement fell through; Lookwell was not picked up; and, burned out, he quit Saturday Night Live . "I told Lorne Michaels I couldn't come back to work and I just needed to do something else," O'Brien recalled . "I had no plan whatsoever . I was literally in this big transition phase in my life where I decided, I'll just walk around New York City, and an idea will come to me ." Mike Reiss and Al Jean, then dual showrunners of The Simpsons, called O'Brien and offered him a job . The series was notorious in the writing community at the time; O'Brien recalls "everyone wanted to be on that show, but they never hired ." O'Brien was one of the first hires after the show's original crew . With the help of old Groundlings friend Lisa Kudrow, O'Brien purchased an apartment in Beverly Hills . He and Kudrow became involved as well, and Kudrow believed he should begin performing rather than writing . O'Brien disagreed, feeling that Kudrow was being overly flattering and that asserting he was happy as a writer . In his speech given at Class Day at Harvard in 2000, O'Brien credited The Simpsons with saving him, a reference to the career slump he was experiencing prior to his being hired for the show . </P> <P> From 1991 to 1993, O'Brien was a writer and producer for The Simpsons . When O'Brien first arrived at the Fox lot, they temporarily gave him writer Jeff Martin's office . O'Brien was nervous and self - conscious, feeling that he would embarrass himself in front of what he regarded as an intimidating collection of writers . O'Brien would pitch characters in their voices as he thought that was the norm until Reiss informed him that no one did such . He fit in quickly, commanding control of the room frequently; Josh Weinstein called it a "ten - hour Conan show, nonstop". According to John Ortved, one of his fellow writers ventured that if Conan hadn't left to do Late Night, he was a shoo - in to take over as showrunner on The Simpsons . </P> <P> When not contributing to others' scripts, O'Brien managed to craft what are regarded as some of the series' most memorable and finest episodes: "Marge vs. the Monorail" and "Homer Goes to College". Generally, critics, fans and even those who worked on the show agree that its sensibilities changed following "Marge vs. the Monorail ." The show was initially a highly realistic family sitcom; after O'Brien's debut, the show took a rapid shift in the direction of the surreal . Along with those episodes, he has sole writing credits on "New Kid on the Block" and "Treehouse of Horror IV", on which he wrote the episode wraparounds . Wallace Wolodarsky described a "room character" Conan put on for the writers: "Conan used to do this thing called the Nervous Writer that involved him opening a can of Diet Coke and then nervously pitching a joke . He would spray Diet Coke all over himself, and that was always a source of endless amusement among us ." Occasionally, fellow writers from the show would stop by O'Brien's Beverly Hills apartment . </P>

When did conan stop writing for the simpsons