“They’re Made Out of Meat” is a short story by Terry Bisson. It’s a great rift of the improbability of the human situation, and particularly relevant to psychologists (e.g. “So … what does the thinking?”)
The full text is here. The story has its own wikipedia page, and there’s a YouTube film here.
Now, for your listening delight Erin Revell and Geraint Edwards, at my request, have recorded the story so I can play parts of it during a lecture. The result was too good not to share, so with Terry Bisson’s permission, here’s a link for the whole thing:
(Cross-posted at mindhacks.com)