Warning: This page features a ton of moments that are guaranteed to leave you laughing. Read at your own risk.
Randy wrote a rather interesting essay◊ in the pilot episode. For those of you who have a hard time reading his handwriting, this is what he wrote.
I spent most of my summer playing Grave Puncher with my BFF (Best Friend Forever) Howard. We beat the first game in seven days. Then we immediately gripped open Grave Puncher 2: Punchocalypse. We beat GP2 (Grave Puncher 2) in (a record breaking) five days, then we immediately moved on to the much anticipated sequel to Grave Punchers 2: Punchocalypse, Grave Punchers 3: Live and Let Punch (aka: GP3). Honestly, it was the most epic awesome game ever made. We beat the game (GP3) in four days. Seriously! Four days!!! And then we beat it six more times in any difficult levels ever existed. Seriously, we even beat the game on the super dupper impossible mode in three days. And the day after that, something even Epic-er happened!!! So I had the most delicious burger for lunch. I decided to go to my room and shapen up my mathematics skills. I found a box sitting on my awesome table. I found the "NINJANOMICON" in the box. And of course the ninja mask. I was like, "Oh, my sweeeeeeeet!" Randy Cunningham is the NINJA. I am the NINJA!!! The sucky part part is that I can't tell anyone not even my BFF Howard! Not becoz he has a big mouth and he will tell anyone. I mean I trust Howard that he won't tell a soul about any of my secerts. But there was a note in the box saying that "I can't tell anyone" which sucks.
Also from the pilot episode, Randy takes his first trip into the Nomicon to ask it for help fighting the Monster of the Week, and its response is "Believe in the weapon that is in the suit". What makes this funny is that Randy immediately assumes it's a Stock Aesop about believing in himself - until halfway through the fight, he starts rummaging through the ninja suit and finds a huge sword.
"Oh. That makes a lot more sense."
In "Got Stank", Howard and Randy are wearing nothing but speedos. Don't ask. A monster starts screaming, and you just know Randy's about to go ninja. Where'd he keep the mask? Inside the speedo.
In "Monster Dump", Bucky worries that Randy is still in danger, while Randy (as The Ninja) assures him that he's okay. Bucky ruins this by saying without Randy (who is his field trip partner) he's going to get detention.
In "So U Think U Can Stank", Howard is supposed to be the mean judge. His first review?
"Loved it. 'Go bros'. You're in the talent show!"
From "Gossip Boy":
McFist: I suppose you're wondering why we brought you here.
Howard: Uhh, 'cause I said I know who The Ninja is?
McFist:... Okay... But, you must be wondering how we're going to let you tell us!
In "Stank'd to the Future", Randy needs to use one of the bathroom stalls for going into the Nomicon. The kicker? Just look at the page image.
The flashback to what the Sorcerer was doing back in the 80's. Turns out, sitting just like his was in the present. Except for another rat (not the same one we usually see) dancing like Michael Jackson.
When Randy accidentally breaks his sword, his first idea is to repair it himself. Needless to say, it wasn't his best work.◊
One of the Robo-Apes' response to seeing The Ninja in a Robo-Ape disguise:
Robo-Ape: Why are you wearing Larry?
Then afterward Viceroy telling McFist that both Marcy and The Sorcerer are calling.
McFist: Give me whoever sounds less mad. (Cue The Sorcerer screaming so loud he breaks all the windows in McFist's building)
Randy: Ninja Rotating-Table-Slide!
When Randy (trying to tell the Robo-Apes to hold their strike until the rollercoaster) by asking them how bad McFist is, you could almost taste McFist coming in to make things worse.
In "Silent Punch, Deadly Punch", Randy has to gather sap from an 800-year-old sacred ninja tree called the Skunk Pine, which is very aptly named...
Randy: Oh, it's awful! But sacred - sacredly awful!
Later on, McFist steals the tree to use as a Christmas tree, as Marci asked him to cut down the tallest tree in the forest. So he cut down an 800-year-old, sacred tree to use as a decoration for his company party...and Randy didn't see that coming, despite all the other despicable things McFist has been involved in by that point.
Pretty much any time Randy opens the Nomicon. He often ends up drooling or Amusing Injuries follow.
Randy getting freaked out by chickens and spouting chicken facts.
When Randy is forced to repair McFist's reputation and the guy still says that he's going to destroy The Ninja, Randy gets him back by telling the town that McFist is giving away free McFistpads, which will cost him a fortune.
In "Randy Cunningham: 13th Century Ninja", we discover the First Ninja has a squire, who also served as a counterpart to Howard. His name is Plop Plop. When Randy and Howard make fun of him, Plop Plop counters by pointing out Howard is a girl's name. Randy laughs at that fact and Howard punches him.
Also in that episode, after Randy and Howard took the Time Machine to the 13th century, McFist asked where did the machine go and Viceroy said it wasn't a matter of "where" but "when". After McFist asked when it went, Viceroy said it had just left a few seconds ago and asked if McFist didn't see that.
"Flume-Igation" has the Shark-Dermanator, a humongous Kaijuu that exists in a perpetual state of flaky-skinned agony that takes breaks from destroying Norrisville and trying to kill Viceroy and McFist for its sorry state in order to scratch its highly irritable carapace.
Randy lengthily entertaining the idea of simply allowing the Shark-Dermanator to kill Viceroy and McFist, thus ridding himself of two of his enemies.
McFist swears revenge on the Ninja...for saving his life and placating the Shark-Dermanator.
During "On the Poolfront", Howard reveals that the water the inflatable pool he and Randy have been swimming in is actually Weinerman sweat.
Mort Weinerman's abysmal killer robot that can barely stand, much less move around. When Randy has to take a dive against it to make sure Mort keeps his promotion long enough for Howard's new pool to be installed, it takes a huge amount of effort to make it happen.
McFist has implemented "McNinja Tours" to profit from Randy's efforts to protect the town.
Randy's fight with the Polar Bear-Bot. It ends with the exhausted, heat stroke-ridden cyborg collapsing and exploding into Ludicrous Gibs due to how hot it is.
Howard's booger story. Which is so nasty, it's used to make Catfish Booray cough up the Power Orb.
The one thing Randy never told Howard: He finds Heidi to be attractive on occasion. Mostly for her accessories and voice.
One of the things that Debbie Kang's articles "ruined" was a two-day school week.
Viceroy managing to weaponize frozen soup to make it cost effective. Even he seems embarrassed about how much of an Epic Fail it is.
Randy's insistence that the pink bag he's using to carry the Power Ball in is not a purse. No one believes him.
Randy so missing his Nomicon lesson that the Nomicon Facepalms at his idiocy.
Randy being unable to remember the name of a band girl as he attempts to rescue her from a Yandere Flute Girl, even after she tells him what it is.
Randy: Clarinet player. I think it was Claire. Or was it Anette?