It's been found. A cyber-archaeological undertaking that rivals any of the pick-and-shovel variety has struck paydirt: the first, honest-to-goodness appearance of the ASCII "smiley."
And you better get out those cards and cameras: his (or her?) twentieth birthday is September 19.
Awesome. It took some research, an ancient 9-track tape drive, and the elbow grease of one Jeff Baird, a facilities worker at Carnegie Mellon University's School of Computer Science. Great work, all.