How bout a rumble/gun game mode where there would be an ordered set of 25 guns and you have to get a kill with all 25 in order to win. You would only be able to use a primary no nades or supers and when u get a kill with your gun it immediately equips the next one in the series till you go thru all 25 [spoiler]I know this is not an original idea i used to love this back when I played cs source[/spoiler]