Kasparov vs. Deep Blue Game 6
Kasparov sucked the big one with 7. ... h6?? which allowed Deep Blue to sacrifice its knight for the e6 pawn and get a collosal attack. This move was well known to be a mistake and most people were shocked to see such a top level grandmaster play it. The move had roughly the same shock value as a 1400 going to a tournament and losing via blitzkreig.