That whole series of strips, in fact. Paige and Nicole attended a college party, only for the host (drunk and stoned out of his gourd) to try and convince Paige to smoke pot or have sex with him, with the sounds of drunken vomiting in the background. When he tries to convince Paige to "do lines" (snort cocaine) with him, she punches him in the nose and the girls leave.
In one strip Jason claimed that Peter likes folk music...because lyrics contains phrases like "folk this" and "folk that." That's pretty daring for a newspaper comic.
Amend actually stated that only one newspaper didn't run the strip that day.
One strip references Shrek's GCPTR by having Paige try to get Peter to let her sneak into the movie. She acts subtle, describing the movie and its cast ("Shrek and Princess Fiona and Lord..."); when Peter refuses, she shoots him a death glare and finishes ("...Farquaad").
Peter's pitching in a baseball game and looking at the catcher's signals:
Peter: Two fingers? Shake him off. Three fingers? Shake him off. Two fingers? Shake him off again. Three fingers? Shake him off again. One finger?... Hey, same to you, pal!
In one strip, Peter was playing Tomb Raider and extolling its greatness to Jason, who refuses to play it because it stars a woman. He eventually says "Lara Croft isn't just any girl, Jason. Check out those twin bazookas". Jason, not getting the innuendo, responds that they are pistols. A later strip, part of an arc where Jason and Marcus recreate video games in the snow after being sent outside, attempt to play Tomb Raider..and the Lara Croft snowman they've made has two large snowballs lying on the ground.
Jason: Dang, they keep falling off.
Marcus: I told you we shouldn't play Tomb Raider.
There's also Jason having an Erotic Dream about Lara, only to spend most of it running away from her. Peter's comments imply that he has wanted one for quite a while.
In the first strip shown there, a character calls George Bush a tool.
This strip circumvented the radar by only being published online as a guest strip for Penny Arcade, instead of in newspapers. It features Jason and Gabe's son doing a web search on sex to find out what it is.