Pretty much any time Ricky demonstrates his expansive knowledge of the law.
This comes to a head in "A Shit River Runs Through It," when Ricky, Bubbles, and Julian are driving down the middle of the river separating the United States from Canada: on the American side, a combination of the FBI, DEA, and ATF; on the Canadian side, Jim Lahey and some Forest Rangers. Ricky realizes that if he doesn't pick a side, neither side can arrest him, so he asks each side how long he and his friends will be in jail, eventually going with the easiest choice. In short, Ricky manages to get himself and his friends off with some pretty minor jail time.
The courtroom scene where Ricky actually gets permission from the judge to smoke and swear in court, and proceeds to defend himself and his friends in court as only Ricky can. Bonus points for having the balls to get the prosecutor to give him a cigarette.
Ricky: Let's go, smokes.
Prosecutor: But I only got two left!
Ricky: I don't care, you've been a dick all morning; it's the least you can do for me.
When Julian finds out the security guards at the mall are making Bubble's shopping cart gathering difficult, he gets gangster on their asses. DO NOT fuck with Bubbles and let Jules find out about it.
The season 9 finale. Julian for once ends the season not by going to jail, but by scoring the ultimate victory: getting ownership of Sunnyvale Trailer Park, and then telling Lahey to get thefuckout.
Early in season 10, some punks bully Bubbles causing him to have a minor breakdown for part of the season. Later in the season, the punks are revealed to be big fans of Snoop Dogg, who personally denounces them for what they said to Bubbles.