Life, observed and examined. A cast of characters go about their daily lives, making observations and being themselves. School is perhaps the most common setting for these kinds of series, especially in animation. Coming of age is often a major part of their stories. They may have Death by Newbery Medal.
What separates slice of life as a genre from the literal meaning of the phrase (which would encompass nearly all fiction) is the emphasis on the very moment, with the intent of focusing the audience on that moment rather than using that moment as part of a narrative. For example, a story about hilarious roommate hi-jinx may depict the mundane life of roommates, but these mundane events are usually the set-ups and punchlines of jokes or part of the conflict between the characters, which takes away their slice-of-life-ness and cements them firmly in the realm of comedy or drama.
Slice of Life series don't usually have much of a plot or, if taken to extreme, even the omnipresentConflict, but they don't really need one, and many Slice of Life stories use a lack of conflict to serve peaceful escapism rather than realism. An example of this would be how in many slice of life school stories, parents are nearly non-existent. Most American newspaper comics that aren't simply gag a day strips are stories like this due to the simple fact that most people do not read newspapers every day and archives of comic strips are rare, so they need to be able to jump into the comic's world at any time and be able to appreciate it.
Slice of life also doesn't have to be set in the world as we know it. Several Webcomics are Slice of Life, while the ones labeled "Real Life" are usually not real life at all, but tend to fall into some brand of Speculative Fiction, or at the least Life Embellished. Not to be confused with the Journal Comic, although they may overlap. For a complete index, see Slice-of-Life Webcomics.
Surprisingly popular in Japan, so a lot of Anime fills this category. In longer-running action-based shows it is also becoming fairly common to incorporate Slice of Life episodes to flesh out the characters by placing them in a more mundane setting. This often gets combined with a Mood Whiplash when the pace of the action picks up. See Schoolgirl Series for a specific type of Slice of Life. See also Iyashikei, which often overlaps with this trope. Compare and contrast with Soap Opera. Since the casts of such shows tend to be mostly if not entirely female, English-speaking fans sometimes refer to them as "cute girls doing cute things".
Slice-of-Life Webcomics have their own page.
BECK: Slice of high school (on the first part of the manga, and almost all of the anime) and rock band life (which makes up most of the manga from the halfway part, and became an Aborted Arc from the anime).
Digimon Tamers: This is a reason why this was a unusual series; Consider that this is a Mon series, meant for kids, without "slapstick comedy" due to being as realistic as possible. Digimon Adventure also had bits of this, but mainly when it was directly affected. Tamers lets us get to know the cast and their lives as it eases us into the story, which goes on to become very exciting and epic. However, the introductory arc has a slower pace and more, well, slice of life tone. Some fans of Adventure and 02 had to be told It Gets Better.
Dobutso no Mori, a.k.a Animal Crossing: The Movie, details a girl moving into a village. No villain, only minor conflicts, and no general plot.
Eureka Seven starts out as a very mellow Slice of Giant Robot life anime. Around Episode 13 it starts picking up in action and darkness, and by Episode 25 it's turned into a nearly full-blown action series. This was intentional on the part of the creators, as they wanted to focus on what happens to characters before, during, and at the end of a war.
Hyakuen: Slice of money-saving high school girls' life, with a dash of comedy and hint of ecchi.
Hyouka: Slice of mystery-solving, high school life. Notably, the protagonist prefers his slice of life to be a little more bland than other people's. Part of his Character Development is him realizing that having an interesting life isn't so bad.
Shanda the Panda, the Spiritual Successor to Omaha, has a similar tone, but confines the sex scenes to their own title.
Most issues of Astro City were actually Slice of Life pieces, with the heroes and villains taking a back seat to the ordinary citizens just trying to keep their lives together in a world where superpowered beings attempt to save-and/or-destroy the world on a regular basis.
It can be argued that Scott Pilgrim both subverts and plays this straight. While the world they live in is clearly a weird video gamed based society where everyone at the least has the potential for super powers, in their world, that is considered the norm. The main plot is essentially the lives and dynamic between all of the characters. When they aren't fighting, everything is actually quite normal, and is almost like a Canadian hipster version of Friends.
One issue was called "Jenny's Day", and was just that: it showed Jenny get up in the morning, go to school, and showed an ordinary day in her life. It was made interesting by seeing her thoughts and how much she hated her life and would rather be living on Zot's world.
Later issues of Zot!, titled "The Earth Stories" did this, focusing on just one minor character and showing a sample of their life.
The Justice League International series by Keith Giffen and J. M. DeMatteis had plots that dealt with these situations in a comedic way, such as Guy Gardner and Ice having a date at an ice show or the team going to a French language school.
The Total Drama story, Legacy begins and ends this way, hence the lengthy discourse on the riveting subject of what Heather and Duncan had for lunch.
Jewel Of Darkness has a chapter near the end of the Jump City Arc showing how each of the Titans (and Midnight) go about their day-to-day lives. Though that said, it does tie into the main Story Arc through Robin preparing to become Red X and is when we first find out Jinx is The Mole for the White Glove.
Anything directed by Yasujiro Ozu can fit into this category quite well.
Otoko wa Tsurai yo film series (literally, It's Tough Being a Man). From 1969 to 1995, it had 48 different installments and held the title of "Longest Running Film Series". All of them are slice of life romantic comedies with nearly identical plots.
A lot of children's books are like this. They may have titles like The Plant That Ate Dirty Socks or Ten Ways To Make Your Sister Disappear, but in the end, they're mostly stories about everyday life happenings, with whatever the title is about in the background as a recurring element, but not necessarily the dominant one.
For example, Ten Ways To Make Your Sister Disappear is really about the everyday life of a girl who happens to have a bratty older sister. Some chapters don't mention the older sister at all, though she's still the main conflict in the story, just not the only one.
Operation: Dump the Chump is about a boy who wants to get rid of his younger brother by pulling schemes like trying to convince a neighbor to adopt him, and things like that. Most of the story is really just about his life and plays out like a series of anecdotes that happen to involve him and his brother.
Nothing's Fair in Fifth Grade has the underlying plot of a morbidly obese girl who wants to be accepted, and the main character, who gradually comes to accept her, and tries to get others to do the same. But the book is just as much about everyday fifth-grade life portrayed realistically and in a fun way, with the totally random hitchhiking scene out of nowhere.
Paula Danziger's fiction.
Adrian Mole: slice of British early-teen-to-forties life.
Nilda by Nicholasa Mohr is about a Puerto Rican preteen, the eponymous Nilda, living in Manhattan during World War II.
Bridge to Terabithia stars two children and their made-of-imagination kingdom and the trials and tribulations of daily schoolkid life.
The Anne of Green Gables series is a classical example: a slice of the life of a woman with writing ambitions (and, in later books, also those of her children and acquaintances) in the late 19th and early 20th century.
Ramona Quimby is slice of elementary school life. The books take place in different years in grade school, from kindergarten to fourth, but all capture that year of life excellently while being very light-hearted.
Despite the horrific murder that kicks of the plot, Boy's Life is mainly about Cory's life in his hometown of Zephyr.
Tamora Pierce's Protector of the Small quartet. Despite the fact that it's about a girl becoming a knight in a fantasy medieval world, there's essentially no overarching plot except for in the final book of the series.
Stuck juxtaposes this together with the oddities rampant within Tre's life in Greyson City, which provides a lot of the humor in the first and second episodes.
Friends, a Slice of Life in New York, as lived by a group of friends who became as tight as a family.
Kamen Rider Hibiki is a tokusatsu superhero show with elements of Slice of Life. The heroes fight monsters, but they and their allies also go about their daily lives. Any drama (to the extent that it is present at all) is very ordinary and everyday-like, in contrast to the more fantastic and more contrived drama seen in many tokusatsu shows.
The British version of The Office fits this model, being the mockumentary of an unexceptional office in a dreary little suburb. The American version continues with the basic premise but increasingly inserts more outlandish sitcom situations.
Freaks and Geeks. Only Lindsay has a really pronounced character arc by the time the series ends.
My Place is this for children's Historical Fiction. The series as a whole stretches from 2008 to past 1788. Some episodes are about big, life changing events, but many are basically about kids getting up to all sorts of fairly harmless shenanigans, and all focus on the kids' daily lives.
The Big Bang Theory is really about the minor adventures of how socially awkward geniuses go about in activities they are unfamiliar with. Especially in earlier seasons, you see them playing games or hobbies with no other plot than just to see them having fun (the World of Warcraft episode opener being a standout).
Jon: I'll have the spaghetti, Irma Irma: Do you want that on a plate? Jon: Of course I do! Irma: Well excuse me, mister picky! Jon: Is it too much to be accorded the same amenities others get?! I'm a person too, you know!! Garfield: I'll just have a small slice of life, thank you
Higurashi no Naku Koro ni is set up like this... until the horror elements begin showing up and it more or less drops the pretense by Kai.
The first part of Kira-Kira with the second part dealing with the casts struggle as a band and the third part being a bit darker.
Shizune's route of Katawa Shoujo has elements of this, which the route's detractors frequently cite as shortcomings. It makes sense, though, as Shizune is said to compartmentalize events of her life and live in the moment, thus not realizing the implications her rejecting Misha's Love Confession has on their relationship, or how her developing relationship with Hisao might exacerbate the problem.
Many Moege's can feel like this during the common route when it usually is just the protagonist, potential love interests and other friends messing around with the plot only picking up during the character routes. Examples include My Girl Friend Is The President, the Da Capo series and Muv-Luv (Extra, obviously).
Acerotiburon by Antonia Pinnola is a webcomic that tends to follow this pattern. Can be found here. The earlier parts of her comic, which involve the protagonist's ex-boyfriend and the characters of Naruto, can be found at her deviantART page.
Botched Spot's original storyline revolves around the lives of two independent wrestlers. A lot more of the story takes place outside of the ring than inside of it and the relationship between the two main characters is the focus.
C'est la Vie, about an Odd Couple sharing an apartment in Los Angeles. Mona is French and intense, Donna is a native Valley girl.
Rival Angels is set in a world where Pro Wrestling Is Real and where women's wrestling is much more popular than it currently is in Real Life. The comic focuses on four female competitors and shows us not only their matches, but also their lives outside of work.
Shiniez takes a good look at the daily lives of people involved in the BDSM scene and all its features and complications.
Squid Row, the life of a starving artist in a sea-side resort.
Pre Teena : Alison Burrows' account of the Keene family of New England. Ivan and Tess are freelance artists with two daughters. The family dynamic is most often viewed through the eyes of eleven year old Teena (the Pre Teena of the title). A webcom about parenting and growing up.
With The Angels is mostly about the protagonist making observations about the people she meets during her stay in California.
Tales of MU is a very detailed and NSFW first-person story about college life in a DnD-like setting.
This trope is commonly invoked when it's an educational book/TV series targeting little kids and is well loved among children book writers and children show producers alike. For example, take Jumbo Pictures'/Cartoon Pizza's show lineup:
Western Animation/Phineas&Ferb was this mostly in it's first season. By the second season, it became this mixed with surreal concepts and by the third season, became less of this and more comedy focused.
Most days in most people's lives follow this pattern of storytelling.