Deep Thought was a computer chess machine built at Carnegie-Mellon University in the 1980's. It was a predecessor to Deep Blue, the chess machine that defeated Garry Kasparov in a match. Neither machine exists at this time.
Andreas Nowatzyk was one of the contributors to the Deep Thought project while he was in grad school. A few years ago when he and I were both working for Compaq's research labs in Palo Alto, Andreas sent me a copy of Deep Thought's evaluation function tuning program and asked me to put it on the Web for him, since he no longer has an interest in computer chess.
If you are interested in this material, you can download it here. Please don't ask me questions about it; I had nothing to do with developing it, and I don't have any information beyond what is on this page.