Kasparov vs. Deep Blue "The Rematch"
Seems to me Kasparov played this too passively , even though in fact he missed a draw by perpetual check ! Here is the drawing line :
45..Qe3 !
46Qxd6 Re8
47.h4 h5 !
48.Qd7+ Re7
49.Qc6 Qxe4
50.d6 Qb1+
51.Ke2 Qc2+
And it's a draw ... I read that when his trainer infored him of this finding after the match he sank into deep thought for 5 minutes , and admitted that he did miss the what should have been relatively easy 6 move line .
On May 4th, 1997, Kasparov played match 2 in a rematch against IBM's 'Deep Blue' computer and lost. Based on some light research on the internet, this re-match was highly controversial and some chess fans have gone so far as to suggest that Deep Blue had some "carbon-based" help (if you will).
Whether or not you buy the conspiracy theories or not, here is Kasparov's first loss against the machine in this rematch.
Eventually, Kasparov resigned even though further analysis by several GMs revealed that he had the opportunity for a draw at this point in the match. Kasparov reportedly admitted later that this was the first time he had resigned with the possibility of a draw.