Deep Blue is the chess\-playing program, built by IBM, that first won the world chess championship from Garry Kasparov in 1996\. Modern algorithms play much better chess, using much less computing power, but Deep Blue still holds the place in history of having first played superhuman chess relative to the best human player at the time\. See http://en\.wikipedia\.org/wiki/Deep\_Blue\_\(chess\_computer\)\.
Actually, Kasparov won the 1996 match with a score of 4-2. This marked the first time a computer program won a single game against a reigning world champion, but Deep Blue didn't win a whole match against Kasparov until their rematch in 1997. (Source: the wikipedia article you linked.)