The Imperial commander's lines in II's Capture The Flag mode. Hearing him say "The Rebels have foolishly dropped the flag," conjures up an image of a Rebel carrying the flag along and then just kind of spontaneously deciding to throw it away because he forgot what he was supposed to do with it or something. "Whoever dropped the flag will pay for their incompetence!" is also a good one.
One of the built-in cheat codes is for "Party Effects Mode". These effects include comic-book style hit effects when someone gets smacked with a lightsaber, and humorous captions when Rebels are killed by Wampas.
On maps in II where the CIS' "hero" unit is Jango Fett, troopers will occasionally remark "It's Jango! And he brought his head!"