In various works that I've read recently, the writers referred to the skeptics several times, and I thought that maybe I should try actually learning something about them. I was hoping for some text that would really introduce me to their philosophy, but still something deeper than, say, Wikipedia.
I would point you at Neitche's "Beyond Good and Evil", Schopenhauer's "The Will to Survive", and Sartre's "Nausea" at the modern end (they are the short forms), Montaigne's "Defense of Raymond Sebond" in the middle, and Cicero's "De Natura Deorum", Sextus Empiricus' "Pyrrhonism", and "The Man in the Tub" about Diogenes of Sinope on the classical end.
I also think Liberation Theologians like George Pixley, who propose political and ethnographic understandings of Christianity and Judaism, and folks who read the Tao Te Ching as a political treatise have a lot to tell us about the deeper motivations and mechanics of skeptical inquiry.
Obviously, for introductory material, I would look for stuff about these people and these books, and not at the primary sources, which are annoying to read.