I saw a thread like this over on the GoW forums (that show up with the "New Posts" link as well, which is silly, but whatever), and I thought one of them here would be nice as well.
So, my own craziest kill so far involved rocket juggling. I was happily on a server full of Sunday-only players (or I wouldn't have led the score board), it was on Deck near the rocket launcher. I shot a rocket at a guy's feet, he must've dodged or jumped right that moment, as it lifted him up into the air, with a fizzling sound from the waning armour. I shot at the wall near him, pushing him upward again, and the third rocket hit him right when he came back to the floor, killing him. Lovely adrenaline rush right there