From Larry Wilde, Great Comedians Talk About Comedy:
Larry Wilde: Is it possible for you to pinpoint exactly when you decided you wanted to go into professional comedy?
Jerry Seinfeld: I was about eight years old. I was sitting on my stoop with a friend of mine. We were having cookies and milk and we were talking and fooling around. I said something really funny and he laughed and spit the cookies and milk all over my face and hair and clothes. And I thought, I would like to do this professionally.