Shinryaku! Ika Musume has Ika with ants. The hard work, the bullying from other ants, feeling sadness for the ant and yelling at kids that were destroying the ant's house so that the ant can return to its colony. Before she knew it, it was already sunset.
Scamper: Our work? You spent the entire time playing with a piece of ribbon.
The TV show from RoboCop (1987). The person watching the movie might find the show's humor asinine; the characters in the movie watching the show find it hilarious.
Dave: I'd buy that for a dollar!
The movie Ass in Idiocracy won multiple awards. It is just a close-up of some guy's ass.
Trolls in the Discworld books gamble by tossing something up and then betting on whether or not it will come down. To be fair, there's definitely some parts on the Disc where it's a legitimate toss-up.
Over Christmas, she took a trip to India, and now she’s in love with what she calls the simple life. She gets serene talking about it; her speech slows and her eyes glisten when she describes an Indian boy who amused himself for hours with a piece of string. I nod, but I think, You watched somebody play with a piece of string for hours?
The Star Trek novel "Immortal Coil" expounds on what the android Ruk (from one Original Series episode) was doing during its long time alone: picking up two rocks of similar composition, putting one in each hand, and squeezing until one is reduced to powder, then adding a point for that specific hand. When plot starts happening, Ruk had reached the point of considering removing a finger from the hand that had won the most often as a handicap.
Little Sebastian the miniature horse on Parks and Recreation is treated like a celebrity by the townsfolk of Pawnee, Indiana. It's lampshaded by one character from out of town who doesn't understand the appeal; everyone else treats him like he's crazy and he eventually resigns himself to faking it in order to avoid conflict.
On Stella, when the boys can't go to the amusement park, they decide to improvise fun rides with what they had at their home; naturally, their alternatives don't quite match up to the real thing, but they make do.
The State had a sketch where two characters play strip poker. Since they're both male and straight, they don't find it all that interesting.
The crew of Red Dwarf have been stranded in space long enough to have some very odd ideas of how to kill time.
Rimmer was apparently always that boring, enjoying such hobbies as Hammond Organ music, morris dancing, studying 20th century telegraph poles, and recounting the events of his Risk game move-by-move.
The others have engaged in such pastimes as watching laundry spin (it was Kochanski's, so this is the closest any of them has to a sex life).
Kochanski herself had a rather sheltered upbringing, with perfect computer generated friends, so her idea of a fun game is humming the various arias of The Magic Flute, and guessing what song it is.
Kryten is a cleaning mechanoid, so he sees laundry and vacuuming as enjoyable activities.
The Cat plays with his food. And by that, I mean pretends his food is alive and he's playing with it like a cat with a mouse.
But the king of this has to be Lister, who spent days crossing the huge ship to get some tomatoes, because he's allergic to them and eating them makes him sneeze, which allowed him to use his snot to iron laundry in order to gross out Rimmer. All that work just to get a ten second rise out of someone. In fairness, they've been stuck on the ship long enough that there probably isn't a whole lot else to do by that point.
JD and Turk of Scrubs have some odd hobbies, like playing "Finger or Toe" in which one of them closes their eyes, the other sticks a finger or toe under their nose, and the first must guess which it is. They also considered switching chairs at their apartment at set intervals to be a major event.
Stargate SG-1. When Jonas Quinn arrives on Earth, he becomes fascinated by the Weather Channel and watches it for hours, to which Carter responds that there are at least five hundred other channels.
"Weird Al" Yankovic's song "Hardware Store" is a song about someone being super-excited about the opening of a new hardware store.
Occasionally used to show how boring a life Jon's family has in the countryside, since the most mundane things excite them such as watching the washing machine instead of the TV ("Here comes the red sock again!"), counting every brick in the wall of the house, taking a trip to see the new water tower, going to the airport to watch the planes take off, etc. This extends to stupid and dangerous things; Jon and his brother Doc Boy mention that one of their favorite games as a kid was called "Touch It, You Wimp!" and involved touching an electric fence.
Garfield and Jon are not immune to this, since their lives are pretty boring too. In one strip, he is watching television when the announcer says, "And now we present, Watching Paint Dry!" Garfield responds with, "Rats! They cancelled Watching Grass Grow!"
In a later strip:
TV announcer: Welcome to Watching Paint Dry Theater!
Jon: It's a rerun.
Garfield: Don't tell me how it turns out!
In another strip:
Jon: Watching the paint dry, Garfield?
Garfield: I hope he doesn't think that my life is so totally devoid of excitement that I am reduced to that. I'm waiting for it to peel.
Jon makes toast... for fun. *pop* "Yee Haaww!"
Jon: I've got an idea, Garfield! I stuff my face full of bananas... then you tickle me!
Garfield: We are the bored.
Sesame Street has Bert, who loves all sorts of boring pastimes such as watching pigeons and collecting paperclips. He even likes to read books like Boring Stories.
Fraggle Rock features the character of Boober Fraggle, whose favourite pastimes include laundry and watching paint dry ...
Hannelore in Questionable Contentthinks that she'd probably find watching paint dry fascinating. Hanners is a certified mega-genius, so big surprise about that whole rant she runs through there.
Scarlet in Sequential Art enthusiastically played noughts-and-crosses with herself and watched for hours how a washing machine works, before "setting sockies free", not that she wasn't established as a Cloud Cuckoolander already.
xkcd: A character in strip #324 finds that tapping different parts of a desk results in different pitches. "So what did you do all afternooon?" "Hung out."
Subverted in the Title Text. "Sometimes the best fun looks like boredom."
If Belkar of The Order of the Stick was speaking the truth, the hobbits in his village played games like "throw the stick", "throw the rock" or "Throw the rock and then the stick shortly thereafter".
A slight jab at canonical D&D halflings there; rock-skipping is apparently a major sport among them.
In "Mid-Life Crustacean", Mr. Krabs hangs out with SpongeBob and Patrick because he feels old. They end up going to the laundromat, reading at the library, sitting in a kiddie pool, et cetera. Of course this is subverted at the end when they suggest a panty raid. But it turns out to be Mr. Krabs' mother's undergarments...
In "The Idiot Box", SpongeBob and Patrick buy a large TV so they can play inside the box. They use their imagination to enjoy it so much, Squidward wants in.
Subverted on another occasion; SpongeBob gets a "useless" piece of paper from Squidward and then uses it to play all sort of games, plus swimming/flying around.
One reason SpongeBob wants to come back to work at the Krusty Krab — he misses the sound of two pickle slices rubbed together. By show's end he's rubbing two pickle slices together and looks ecstatic.
Homer Simpson does this a lot, like playing with the adjustable hospital bed in "Homer's Triple Bypass": "Bed goes up, bed goes down! Bed goes up, bed goes down!"
Milhouse with the cup and ball. A joke Family Guy then did years later.
Marge actually gets thrills out of monotonous activities such as household chores and evening walks (of which she tends to prefer the dullest route). The family actually tend to find doing Marge's ideas of fun more unbearable than Homer or Bart's troublemaking.
Seymour Skinner is this trope personified. When Bart forgets his field trip permission slip, he has Bart lick envelopes all day and suggests to make a game out of it by counting how many he can lick in an hour and then try to beat that record. It's so dull that it makes time go slower and skip backwards one second.
Dexter's Laboratory: In "Old McDexter", Dexter visits an Amish community. When he tries to explain "fun", the Amish lads can't think of anything more exciting than the butter churn. When DeeDee (who got to go to Space Camp) arrives, she adds insult to injury by agreeing that churning butter really is the best thing ever.
Fanboy and Chum Chum: In the "Night Morning" episode, Fanboy invites his whole class to watch Chum Chum do his morning routine... AT NIGHT!
Invader Zim: GIR enjoys a lot of activities others wouldn't. Like hiding inside a cooked turkey for hours.
Phineas and Ferb's activities are usually the exact inverse of this trope, but in "Phineas and Ferb Interrupted" they get hit with Doofenshmirtz's "Dull-and-Boring-inator" and spend most of the rest of the day playing with lint rollers and watching grass grow.
In "Lesson Zero" it's revealed that her favorite toy growing up was a "Smarty Pants" doll, which comes with accessories like a notebook and pen so you can pretend that she's studying. Twilight considers this the most awesome toy ever.
Maud Pie, sister of Pinkie Pie, is only interested in rocks. This, combined with her perpetual Dull Surprise expression, makes it incredibly difficult for Pinkie's friends to bond with her.
Numbuh 4 of Codename: Kids Next Door loves getting buried up to his head at the beach. He even has a little song for it.