I have a few even though I have only been really playing for a few months.
Eldar v. Chaos: neer the end of the game, his dreadnot decides to bloodfrenzy at the last minute, charging my farseer and one remaining warlock. Farseer misses with all of his attacks. Warlock steps up and destroys the dreadnot with his witchblade. game ended in a draw due to the death of "Tex" (the dread). it was priceless.
In a cleanse mission against 13th company (I think). most of both of our armies are dead by the end of the game. all he had left was a pack of wolfen, and all I had was one vyper with both of its guns missing. Alpha mission, though so we tied. the vyper had been shot at several turns by plasma and rockets, but survuved. it was charged at least four times by a whole pack of wolves, but never died.
Against a demonhunters army, gray knight temranators deepstrike near my Avatar, but fail to notice the banshees right behind them. they failed to wound the avatar in shooting, then got wiped out by the banshees. at the end of the game, I had lost a total of two rangers and one guardian out of 1500 pts. he had only one squad of grey knights left on the board, under half strength.
3way against tau and space marines. one squad of guardians, no warlock, one rocket launcher killed off a whole squad of sniper drones and spotter in one turn. next turn, all but one guardian die to fire from a stealth team, he passes moral check. next tunr he passes man alone check and fires his missile, killing a land raider on a glancing it of 6! I killed all three of the SM's vehicles that turn on glancing hits...