In conversation and in print, Andrew Pessin is as witty as he is approachably profound. Perhaps it's not surprising, then, that in 1994 Pessin appeared several times on "Late Night With David Letterman." He had a role in a recurring skit called "The Strong Guy, the Fat Guy and the Genius" - and, yes, Pessin was the genius.

In each episode, Letterman would lead the three into a variety of establishments, where the the Strong Guy would break something, the Fat Guy would eat something - and then Pessin would answer some arcane question.

"I was finishing my Ph.D. in philosophy and I knew someone who was interning at 'Late Night,'" Pessin says. "They wanted to put the skit together, and my friend suggested they call me to audition." He was one of three candidates; one looked too much like Strong Guy and the other, Pessin says, "was super nerdy. I was just the right amount of weakness and nerdiness, so I got the job."