In episode 1, Rin grumbles about how ridiculous reducing the Holy Grail War into a game show is, and how she's going to manipulate and cheat her way to victory. What does she do when the camera pans in on her? Cute mode!
Repeated on the 9th episode, only reversed: Cute mode first, then manipulative and cheating mode.
Archer: In other words, we're doing things like usual...
The entire damn volleyball game, which includes such gems as:
Ciel getting repeatedly beaned in the face with a volleyball, both intentionally and accidentally.
The girls bringing out all their powers for the game, including Akiha's Vermillion mode, Ciel's Seventh Holy Scripture and Arima's martial arts. And then Arcueid drops the moon.
Shirou desperately trying to repair his ship, only for the aforementioned powers to cause the volleyball to punch holes in it. As well as his brief meeting with Shiki later.
Shirou: I couldn't fix the rocket.
About that rocket? Shirou wasn't the only Fate/stay night character in that rocket. Lancer was taking a nap there and the volleyball manages to hit and KILL Lancer yet again.
And finally, during all of this, Len was making a sand castle. By the time they're done, it is a freaking sand mansion. She's literally on top of it.
When they have the notice for the prizes, the Team Award (year's supply of rice) is funny enough, and the MVP award is the entire reason all the above happens (a private room with Shiki for the night). But what takes the cake is the Nice Attack Prize: a T-34 tank.
Gilgamesh showing up and pulling out a Game Breaker. They had already established that Noble Phantasms were against the rules, but he goes ahead and uses it, with hilarious results.
He pulls it off a second time during the later montage, only every weapon coming forth is a piko piko hammer.
And in what might be a shout-out to descriptions of Gilgamesh as 'the original BLANK' Caster calls him 'the oldest bully in human history'.
Archer's comment near the end sealed the deal: he reminded Rin that Shirou had told her exactly what to do when he asked her to record a show, and that she was needlessly complicating things. She still manages to screw it up (mostly by pressing random buttons), although at least she ended up recording something.
Made even funnier when you remember Archer is a future version of Shirou so he probably knew from the beginning how this would end.
The tennis match in episode one. Especially Berserker's expression when he gets disqualified.
And Caster arrives in a mini-skirt and without an ominous aura, causing other masters to start asking who the heck is she supposed to be.
Shiki and Shirou's respective Zany Schemes for dating everyone in their harems in the same day.
The entirety of Berserker's First Errand in episode 5. Going to buy batteries could not be funnier. Or to put it this way: How to win the Holy Grail War by shopping for batteries.
The entire segment was hilarious, true. However, the absolutely funniest moment was when Berserker, who, after losing his axe-sword early on started wieldingLancerlike a club, ends up having him become his Noble Phantasm, complete with status screen.
One that deals extra damage to Archer, to boot. And during his errand, Berserker managed to defeat every other servant (with the exception of True Assassin, who probably doesn't even exist there) by pure accident (other than Lancer, who at least got the death he was so wishing for).
Assassin and Rider have some very memorable and downright hilarious screams when they get defeated.
The segment would have been pretty funny on its own, but it's the children's show-style narrator that really pushes it into over-the-top funny territory.
Nrvnqsr Chaos, Kuzuki Souichirou, and one table in a restaurant. Kuzuki is so Comically Serious that it's funny.
The beginning of episode 4. We don't know what they have against Lancer, but they seem to be having a lot of fun.
Commenter: A man in blue full-body tights was just caught in a series of car crashes with a trailer on a highway. He died.
That example counts as a Continuity Nod as Lancer got hit by the car in the previous episode's Phantasmoon segment. In the next Phantasmoon segment (also in episode 4), he's the one Akiha is feeding to the dog.
Lancer is the ass of almost every joke they can possibly throw at him. This includes dying in every episode except 2, worst being casually and for absolutely no reason thrown to Saber Lion as a snack. They love to hate the poor Servant.
However in Episode 11, he manage to dodge all his deaths from previous episodes...only to die at the revisit of episode 2 by a volleyball. Or did he...?
In episode 12, Kotomine complains to Grail-kun that Lancer is useless because he keeps dying. Grail-kun's solution is to give him a "Servant Strengthening Device".
Grail-kun:You should just kill him and forge a contract with another Servant.
Kotomine:(as he pulls the knife out of the floor) You're right.
Gets a Brick Joke in the HibiChika special where Lancer is revealed to have been killed by lots of Kotomine's Black Keys... and one "Servant Strengthening Device".
Lancer protecting himself from Rider's attack in episode 11 by throwing Shinji into the air, causing Rider to turn and charge at Shinji instead (or rather, she was always trying to hit Shinji).
The fact that Arc always remains unfazed about all of the shenanigans around her is hilarious, especially in episode 11 when even Grail-kun appearing right next to her doesn't cause any problems.
Arc stepping on Neko Arc prior to the volleyball game is made that much funnier in the context of Neko Arc's line about the girlhood of humans being a fleeting moment.
Assassin's bind to the gate of the temple. Not only does it make him absent in most events(having to be replaced by a cardboard cutout instead), but him during the race where he literally took the whole gate with him just to be there...
Saber sobbing whenever each segment ended and Shirou denied her food because she didn't get the first place. (which is always accompanied beforehand with Shirou yelling "SABEEERRRR!!!"
Ilya and Caster arguing about the values of mature and sexy women.
Ilya: Mature women has no values these days!
Caster: What did you say!? You just don't understand the charm of mature and sexy women, you lolicon doll!
Ilya: Shut up! All Japanese are lolicons!
During the final boss battle, Saber attempts to calm Ilya down by telling her that she is not an Eizbern doll, her parents loved her and that she is free to choose her own path. It appears to work but then a Japanese manual of assassination pops out of nowwhere convincing Ilya that Saber is just trying to trick her and resumes fighting.
Cue Kohaku facing obstacles like Invisible Coin Blocks, replaying fighting scenes from Tsukihime, Unlimited Blade Works and Fate/Zero, to tell Akiha that Koha-Ace is animated only to realize that she used up all the budget in the action scenes and Saber's fee just now.
Saber being called Type-Moon's cash cow.
Akiha and Kohaku being upset that the Tsukihime remake takes so long and blaming Nasu for slacking.
Neco-Arc and Neco-Arc Chaos commenting that Lerche managed to animate characters that are even more half-assed than themselves.
If Kohaku had known how much Saber costs, she would have invited Saber Extra instead. She does it anyway.
Arcueid needs a pig to prepare okonomiyaki. Her solution? Mugging Nrvnqsr Chaos for the pig among his beasts.
Arcueid gets another one just by being herself in episode 11. There she is, sitting next to Eldritch Abomination Grail-kun... munching on her snacks like normal and watching it while it talks whereas anyone else would have been running away, screaming in terror.
Nrvnqsr is involved with two in the EX episode: First where he and Roa are portrayed as The Woobie and second when he's completely stumped after being asked to spell his name.