The Thirty Second Bomb. In a fighting force that routinely uses Flame Throwers and atomic weapons in combat, this is the weapon that Rico feels bad about using. It is designed to loudly announce in the target's native language that it is a bomb, and then issue a loud verbal countdown to induce an appropriate response. Rico causes a stampede by tossing it into a Skinny command center.
Rico's Un Paused moment late in the book. He is protesting his commander's decision to use a post-hypnotic suggestion to make Rico take a nap. His commander doesn't seem to know what Rico's going on about, and Rico soon realizes that he was put to sleep halfway through a sentence, waking up hours later and continuing without missing a beat. Nevermind the humorous situation of a Space Marine refusing (futilely) to take a nap.
This line would be even more funny if it didn't lead to tragic consequences for Zander later on.
Carmen:(after giving her location to Rico) The situation is... (takes a look around to see that they're surrounded by bugs) Situation is extremely hostile!
Carl and his pet ferret Cyrano, "Go bug Mom!".
Carl: I gave him the impression that there's a grub crawling up my mothers leg, he's on a mission to go eat it.
Carl's Mom: (banging noises can be heard upstairs) What are you doing?! GET OFF MY LEG!! AWWWW! ...Carl!
And then, Colonel Rico shows up, while the medics are collecting the various dismembered body parts from the explosion. He turns to one of the surviving troopers, motions to a nearby severed arm, and gives us this line:
Rico's new squad have to strip naked as part of the preparation for being paired with their Powered Armor. For some reason. One of the guys is a bit shy, and strips last. Cue the female trooper next to him coyly Eating the Eye Candy and remarking "Now we know why his momma calls him 'Slug'."
Daugherty shouting at the John A. Warden as it departs abruptly during their evac mission on Fort Casey.
Daugherty: Thanks for waiting, Jackass!
Holy Man is having an argument with the local Hollywood Atheist (who primarily argues by quoting famous Atheist writers), who snarks that religious men never say anything worth writing down. Holy Man replies with a quote about how men who stare at the abyss are afraid of the light...