Seeing Leslie Lamport's first paper (about braids, for a high school math journal) makes me want to put together a list of computer scientists' first papers. Now I've got two favorites:
Leslie Lamport, "Braid Theory": http://research.microsoft.com/en-us/um/people/lamport/pubs/b...
Don Knuth, "The Potrzebie System of Weights and Measures", Mad Magazine: http://upload.wikimedia.org/wikipedia/en/5/52/Potrzeb.jpg