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 Sam Losco turns out to be the reason Bubbles kitties are getting sick, due to them eating the dirty hot dogs he's been throwing around, Julian forces him to clean them up by giving Sam a simple choice: 1. Clean up the hot dogs or 2. Get the shit slapped out of him in front of Barb.
Ricky forcing Randy to put on a shirt in the barbecue episode
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.
In season 8 Julian challenges Cyrus to put his gun away and fight him like a man. Dirty Coward Cyrus tells Sam to "deal with" Julian for him. Julian proceeds to knock Sam out. With one punch. WITHOUT SPILLING HIS DRINK.
Sebastian Bach telling Cyrus and Sam nobody likes bullies, followed by him firing at their feet. "Dance motherfuckers!"
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.
In season 11 Randy while trying to get into the police academy starts acting tough with the boys, and threatens to forcibly remove Julian from the park. Julian promptly grabs and twists his nose until he begs for mercy.
Ricky pulls one if his best getting-out-of-trouble tricks of all time in season 11, telling a cop he's under cover and convincing the cop to hand over his gun and the weed he'd confiscated earlier.
After George Green spends all of season 11 using his new role as Chief of Police to pull his greasiest stunts yet (from detaining the boys for a week without charge to blackmailing their lawyer so they can't sue, just as he's about to take the boy's massive profit from this season's scheme as "evidence", he's arrested by internal affairs.