This was not staged; it happened on the Grifball map Aeriel (i think) with the low gravity setting. I was running the ball to the enemy plant zone, and they started whacking their hammers at me, and i just kept going up and up and up, and before i knew it, i was standing on top of the map! I even managed to get down and score! http://www.bungie.net/Online/Halo3UserContentDetails.aspx?h3fileid=103113919