Being Kinnikuman, the series is filled with these.
Any time Mari's involved in a storyline before the Re Tool. Kinnikuman and Meat would often fight amongst each other to impress her (despite the latter being 12.)
In one chapter, Kinnikuman decides to leave Earth to visit Planet Kinniku. Surprisingly, the townspeople bid him a tearful farewell. As soon as he leaves, cue the townspeople celebrating Kinnikuman's departure. Then cue Kinnikuman returning angrily, saying that he knew they'd try something like that and that he saw the whole thing from above.
Later in the same chapter, after stubbornly refusing to fight Dai King, he finally agrees when Meat's hot sister, Medium Rare, asks him to (complete with Kinnikuman telling Meat to call him "Big Brother"). Then The Stinger comes after Kinnikuman defeats Dai King, as it turns out that Medium Rare is engaged. That doesn't stop Kinnikuman from asking Meat about his other sister, who is revealed to be a Gonk.
The ending of the Roots Island saga. Kin, Terry and Meat get paid in money, but it turns out to be money made out of stone.
Roots Island Princess: Here is the Roots Island equivalent of one billion yen. Please accept it.
Terryman:What the hell era are ya'll livin in?!
Kinnikuman: We can't use this stone money! No matter how much it's worth!
Mari and Natsuko's first meeting in the anime manages to be a Dude, Not Funny! moment and a Crowning Moment of Funny at the same time. Natsuko accuses Mari of being The Vamp, with Kinnikuman agreeing on that fact and say that he's the 69th to be deceived, but he was joking. Then, when he tries to say that it was a joke to a now weeping Mari, Mari tells him that he's actually the 100th. Cue Ocular Gushers from Kinnikuman.
Mari: See? Not a very funny joke, is it?
In "Flying Natsuko", Iwao tries to persuade Natsuko to take pictures of his fight against Kinnikuman...via haggling.
Iwao: 10,000 yen!
Natsuko: 5,000 yen!
Iwao: 3,000 yen and I ain't going lower than that!
The fact that not only does he lose to Kinnikuman, but the fact that Kinnikuman doesn't so much as break a sweat against him. Pre-Cerebus Syndrome Kinnikuman, mind you.
Iwao:Why was I even in this episode...?
It doesn't end all badly for Iwao because, the real hero of the day turns out to be Terryman, who only had a minute of screentime. Though that was only because Iwao stole the film containing the pictures from the fight...
In the 20th Choujin Olympics, Iwao shows that being Kinkotsuman's lackey doesn't stop him from taking swipes at his boss.
Chapter 82, starts off with Kinnikuman's dad Mayumi waking up for the new year only to find out that Kin lost the championship belt due to not being there on time. It only gets funnier from there, when Kin visits him with the belt apparently still with him:
Sayuri: Oh, that belt is?
Kinnikuman: Fool, it's the world championship belt.
Mayumi: Making one out of papier-mache...(rips up the belt)...is useless...
Kinnikuman: Oh...so you knew...and I stayed up all night making that...
The beginning of Chapter 83 where Bibinba becomes an over-the top parody of Chickification: acting like a Girly Girl, peeling potatoes and wearing kimono, much to the distress of her father.
Lord Hormon: Bibinba, those clothes?!?
Bibinba: Oh Dad, I am a girl, you know. Shall I peel you a potato?
Chapter 84 in the manga, especially the ending. After spending the whole chapter trying to earn Kinnikuman's approval and stay by his side, Bibinba announces that she's joining the Earth Defense Force, rivals of the Choujins. Of course, this means she won't be around as often. Kinnikuman's response to this is the icing on the cake.
Kinnikuman: What ever happened to not ever wanting to be away from me?!? Come on, independent women are out of style!
One fight during the 21st Choujin Olympics features Cubeman, a man with a Rubick's cube for a head fighting Mindpuzzleman, a walking ring puzzle. Rather than wrestle, they take turns trying to solve each other. Eventually, Cubeman seperates Mindpuzzleman's rings, winning the match.
Kinnikuman: What an unbelievably idiotic victory...
While the Scramble for the Throne arc probably contains the least jokes, there are some funny moments, particularly when Mayumi unabashedly cheers for Suguru...despite the fact that the rules say that he's supposed to be neutral because there is no proof that Suguru is his son. Further made hilarious when his guards have to remind him via aiming spears at his head.
Mayumi: Yeesh, I'm being treated like this by the soldiers that obeyed me until yesterday...
Kinnikuman Mariposa's hilariously awkward reaction to Mixer Taitei's Kick the Dog moment shows that even a guy like Mariposa, who was a Street Urchin that's probably seen every sort of villainy can be rather confused by pointless cruelty.
There was a 3-month hiatus between chapters 315 and 316 due to the writer of Yudetamago being sick. any other series would start back up where they left off, but not Kinnikuman. The first thoughts he has in 316 is how painful it's been to hold the same pose for three months, especially since now he's stuck. he looks to Robin Mask for help, only to see that he's asleep!
Robin: Oooh... Sorry, very sorry... Somehow I went to sleep since I've been standing in the corner for three months too.
Another crowner for the Throne Arc: Kinnikuman thinks up a surprisingly brilliant plan to escape the labyrinth that Super Phoenix had set up for his team. Robin Mask commends Kin, but then Kin mentions that he was burning to take a piss from earlier but he couldn't take off the suit that he wore in his match against Satan Cross. This wouldn't be so funny if it weren't for the fact that when he says this, Robin was carrying him on his back. Cue Ramenman having to stop Robin from beating the crap out of Kinnikuman.
In the very first chapter, the military prepares for the threat of an alien invasion...by having wrestling matches.