I've been reading the Second City almanac of Improvisation, by Anne Libera. Here's an excerpt from an article by Tina Fey:
I'm always surprised when I meet someone who thinks that sitting and writing is the only way of creating comedy. It's like meeting someone who thinks that in vitro fertilization is the only way to make a baby. You want to say, "No, there's this whole other way of doing it that's natural and sometimes pleasurable."
Damn, I love that woman. I think I read Bossypants in one sitting.