Hmm...
Aside from the Naruto ones others have already mentioned, the first funniest thing that comes to mind for me is in DBZ where shortly after Kid Buu blows up the earth, Hercule goes all crazy and starts thinking the whole Buu thing was all a dream, and then he jumps off a cliff (thinking he could fly).
The Elder Kai said "Heh. You can't pay for entertainment like this."
So true. 😂
The ones that immediately comes to mind are, in SGT. Frog, they were going to swim in gym class and Natsumi's friends were talking about how jeolous they were of her and her figure, and out of nowhere they started grasping on to the body parts they wanted, then in the next shot the author apologizes and says that he couldn't help himself(It's weird to see something so out there without the frogs, completely unexpected), the other was when everyone was telling horror stories, and Moa, intergalactic destroyer of worlds, doesn't understand and starts telling a whore story instead.
I love the baseball episode of champloo as well.