In the Season 6 finale, when Monk finds the hitman who killed his wife, even though he has a gun with him, Monk just lunges at the guy and starts beating and kicking the crap out of him.
He also gets a couple of good moments when up against a shock jock. The episode deals with the insecurities Monk feels about his general lack of humour compared to the apparently hilarious DJ Max Hudson. He goes on Max's show, and it goes well until Max jokes about Trudy's death, prompting Monk to leap over the table and attack him. Then, at the end of the episode, when Monk's finally figured out how Max killed his wife Jeanette and gotten him placed under arrest, he solemnly tells him "you're not laughing... now... are you?" Max Hudson says "No. I'm not" and Monk replies "Join the club".
Then there's his response when he manages to get his Arch-Enemy Dale 'The Whale' Biederbeck arrested for murder in their first encounter in the series; Dale, who is grotesquely overweight, lunges at Monk to try and throttle him, but can't quite reach:
Sharona Fleming: What's he doing?
Adrian Monk: [highly amused] I think he's trying to kill me.
[Monk leans in towards Dale, though he stays inches out of reach. Dale eventually gives up in frustration]
Adrian Monk: It wasn't much of a fight, was it?
In the Season Four episode, "Mr. Monk and the Astronaut," Monk runs out onto a military airstrip and stands in front of an F-22 fighter to prevent Steve Wagner from taking off to dispose of evidence.
And to top it all off, when it finally comes to a halt in front of him, he uses his sleeve to polish the nose cone.
Plus, he stands his ground with the laser sights of several rifles pointed at him, which had earlier caused him to completely flip out.
In the Season Two episode, "Mr Monk and the Paperboy" when reading a newspaper (he was trying to find out why someone would kill the paperboy over it) Monk solves a hit and run and a murder in France, before finding the actual reason the paper was stolen.
To fend off a bear in "Mr. Monk goes Camping", Monk tells it a story. And it backs down.
From the episode in which Monk gets his badge back is the confrontation with Mikhail Almonov, who murdered SFPD officer Russell DiMarco. While Monk does fall for a Have You Told Anyone Else? moment, what happens afterward is all sorts of awesome - when Mikhail tries to drop him from the scaffold by tilting and shaking it, Monk pulls himself up from the bottom, stabs said guy in the leg with his badge, and then throws away his pistol before suspending him upside down from the scaffold, all while terrified by being many stories off the ground.
Made even better by his one-liner when announcing his retirement from the force.
Officer: You're turning in your badge?
Monk: He has it.
In "Mr. Monk and the Captain's Wife", Monk jumps into a GARBAGE truck to grab the incriminating evidence against Evan Coker.
This deserves elaboration. Leland's wife Karen has been hospitalized after someone shot a tow truck driver, causing the truck to swerve into the path of her oncoming van, and she collided with the car the truck was transporting. Despite Monk identifying Coker as the guy who committed the shooting, as well as shot another truck driver at the truck depot, they are unable to find the evidence needed to arrest Coker: the MacGuffin that Coker was after (the car was his, and it was being repossessed; he was trying to grab a pistol he had stashed in the glovebox that connected him to another crime), and a pair of shoes that he took off the driver (as Coker hadn't had time to get his shoes on before racing out the door with his rifle to shoot the driver). Monk then hears a garbage truck being loaded and realizes that today is garbage day, and runs after the garbage truck, jumps on and flings the bags out of it. After a few minutes of searching, they find one garbage bag containing the pistol and the driver's shoes.
The finale: Monk waits outside Judge Rickover's house and makes him dig up evidence at gunpoint. While near-death from poison.
Adrian Monk: Your garage was open. I borrowed a shovel.
In "Mr. Monk and the Game Show", Monk realizes how Roddy Lankman is helping Val Birch cheat (he indicates the right answer by the corner he's holding the question card from) and makes it to the bonus round (to expose the murder) by defeating Birch with his own method.
In "Mr. Monk Stays in Bed", when Natalie is taken hostage by a criminal and brought to the dump in order to find a piece of evidence that could get him convicted, Monk manages to come in, tackle the guy, and then beats him down with trash long enough for the police to arrive. Oh yeah, and at the time Monk also happened to be sick and wearing nothing but his pajamas and bathrobe at the time.
Just to elaborate, Monk. Weaponizing garbage, his true nemesis. And succeeding.
Monk and Willie Nelson, on clarinet and acoustic guitar respectively, serenading Trudy's grave.
"Mr. Monk and the Leper": Monk is contracted to testify that Derek Bronson is not, in fact, as legally dead as he appears. Given that his testimony is shaky (they met in a dimly lit bar and parking garage), the judge heading the proceedings decides to test Monk's observation and memory and asks him to first turn around and then to describe his shirt.
Adrian Monk: You cut yourself shaving, and there's a tiny drop of blood on her collar.
Judge Lawrence Barr: What are you implying?
Adrian Monk: You were having a sex affair with her on that couch. The cushions are backwards and one of her earrings fell off. So, itís right here. Under here. [Monk walks over to the couch, picks up the earring with his tweezers, and sets it down on the table] She must have torn her blouse. I can see it sticking out of her briefcase. Your honor? [beat]
Judge Lawrence Barr:Iím ready with my decision. I will accept Mr. Monkís word that he met with Derek Bronson. Therefore, Mrs. Bronson will retain control of the entire estate.
Monk's first case, as described by Stottlemeyer: A woman had supposedly committed suicide by overdosing on pills. Stottlemeyer called it suicide, every cop on the scene called it suicide, the medical examiner called it suicide. Monk walked in, took one look at the room, and called it murder. There was no water in the room, so the victim could not possibly have consumed the large pills by herself. Eight people were in that room, only one noticed that detail. As Stottlemeyer put it:
Stottlemeyer: There is only one Adrian Monk.
In "Mr. Monk and the Earthquake", Captain Stottlemeyer arrives just in time to save Sharona from being knifed by Darryl Wright. He grabs Darryl's knife arm and twists it behind his back, causing Darryl to swear in response to the pain.
How about The Plan she pulls in "Happy Birthday, Mr. Monk"? She put one over on Monk.
Randy saves the day in "Mr. Monk Gets Married," where Dalton Padron has married Randy's much older mother. He finds the body of Padron's partner and arrives just in time (after Monk, Sharona, and assorted extras have been locked in a closet) to stop him from fleeing the scene and to heroically demand, "Where the hell is my mother, you son of a bitch?!"
Moments where Captain Stottlemeyer demonstrates Monk's power of perception:
"Mr. Monk Is Up All Night": realizing that the tissue he was given in Jacob Posner's coin store is actually a cocktail napkin from a place that he previous claimed to have never been,
"Mr. Monk Makes a Friend:" figuring out Monk's new Poisonous Friend Hal Tucker is using him because he knew that Tim Hayden was pistol-whipped instead of shot (due to the firing pin being worn out):
"Mr. Monk Goes to Vegas": Solving a murder just by looking at the inconsistency of the victim's earrings in a photograph of her as she was when last seen alive, and as she looked like when first found dead... while drunk.
"Mr. Monk Is Up All Night:" Randy stopping criminals while dressed in Captain America PJs. While drunk. With a garbage pan lid for a shield. The only reason it works is that the criminals are still trying to figure out how to react when the proper, non-drunk cops show up.
"Mr. Monk Goes Camping:" In the span of a few seconds, Randy goes from being unarmed and sneaking up on Luke and Del Johnston to holding a rifle in his hands and forcing them both to surrender. Moments like these we realize why he's still a cop...
Sharona giving a piece of her mind to a teenager who threw a chalk duster at Adrian:
Sharona Fleming: Look, I know when a man's lying, okay? I was married for three and a half years.
Kyle Patterson: I didn't do it.
Sharona Fleming: I know that smirk. My husband had that same stupid smirk on his face when he got back from Bally's, where it turns out he spent the weekend with Betsy Bennett, his so-called "ex-girlfriend"!
Kyle Patterson: Bally's, lady? What are you talking about?
Sharona Fleming: Is that chalk on your hand? Maybe I should call your parents.
Kyle Patterson: You don't have to. My dad's a gym teacher here, and he's gonna be pissed!
Sharona Fleming: I'm really scared.
Kyle Patterson: You should be.
Sharona then stamps on his foot.
Kyle Patterson: Ow! You're gonna get fired, lady!
Sharona Fleming: Yeah? I don't work here, chum.
In "Mr Monk and the End (Part 1)", Stottlemeyer needs some info from a fixer to catch Monk's killer. He tries yelling, he tries pleading for his friend's life, but the fixer taunts him by asking if Stottlemeyer is going to hit him with a phone book.
Fixer: People don't use phone books anymore! They use computers!
The writers get one at the end of the episode, when we find out Trudy's present for Monk, the one he never opened, contained a video message in case something happened to her. The same present they've mentioned throughout the entire series.
At the end of Mr. Monk and His Biggest Fan, Randy gets one. Throughout the episode, he had been wasting time playing a Jenga-like game, much to the annoyance of Stottlemeyer and the amusement of the others. When confronting John Ringel in a warehouse filled with large bundles of wood, Randy lifts out a long 4x4 piece of wood and shoves it back through the hole, hitting Ringel on the other side and knocking him out. "Stupid game, huh?"
Natalie and Sharona teaming up to beat Perry Walsh into submission in "Mr. Monk and Sharona".
In Mr. Monk and the End, Stottlemeyer and Randy are racing to stop Monk from killing the judge. Their way is being blocked by a slow delivery truck which is reluctant to get out of the way, so Stottlemeyer pulls out his gun and fires into the air to make it move.
In Mr. Monk and the Blue Flu, Monk and Natalie are put in charge of the homicide division of the SFPD by the mayor. The mentally-impaired detectives he has all get some awesome moments, but especially Jack Wyatt, when he does a Shoot the Hostage ploy on a serial killer captured in a SWAT raid.
In Mr. Monk and the Dirty Cop, Natalie unflinchingly training a gun on someone.
In Mr. Monk Goes to Hawaii, we see Monk demonstrate that he can be protective of Natalie when someone tries to prey on her personal emotions.