By this time, Reiss had moved on to the animated hit "The Simpsons," and he wanted his fellow 'Poonster on his team.

"Conan was the first guy we wanted to have," Reiss says.

The show started with steady staff of eight writers, but Reiss brought in O'Brien when the show had two unexpected vacant spots in 1991. "What I could not believe about the guy is that he is funny all day long," Reiss says. "At midnight or 1 a.m. he'd still be funny."

When O'Brien was alone in his office, "he was still doing something kind of funny, just to make himself laugh."

And nobody worked harder than O'Brien. In only his third day on the job at "The Simpsons," he successfully pitched what became O'Brien's favorite self-written episode, entitled "Springfield Gets a Monorail."

Reiss says he considers the episode one of the best in the show's 10-year history.

"I wish we had him back writing at 'The Simpsons,'" Jean says.