Anime’s take on culture and sport festivals – Fact, and perhaps what I'd consider the most accurate depiction of all.
So as most people who watch anime know the culture and sport festival are two of the biggest school events during the entire year and what you see portrayed in anime is about as true to life as you’ll get.
First the culture festival, this is probably THE big event of the school year. They typically seem to take place in September or October, but can be as early as June or as late as November. High level schools seem to have them earlier, like before summer vacation, that way students can focus on studying during the second half of the year. Students will start getting ready 3 months in advance sometimes. Like you see in many shows it all starts with a student voting process. You’ll have the class leaders and culture festival leaders come to the front of class and then it’s a democratic process of nominating ideas and voting for what students want to do. That is followed by deciding who will do what job for their given activity. Then that is followed by roughly 2 months of preparation. Of course it’s not every student working every single day, but you’ll have students working on and off on given days. Since different students will have different jobs some students might only have a week of work at the very beginning or need to work a couple days tops depending on their specific job.
Just like you’ve seen in shows like Haruhi Suzumiya, Kimi ni Todoke and Azumanga Daioh you’ll see students dressed up in all kinds of crazy costumes, performing live concerts, cooking food, doing maid cafes and ghost houses and all sorts of other random stuff. Clubs will normally put something together. If it’s a club such as art, dance or calligraphy then it’s pretty obvious what they will put together, but the sports clubs might put on a little show depending. They will last for two days and be open to the public at least for one of the days so it’s also a chance for the school to make back some of the money it lost paying for all the stuff that went into making everything. When all is finished the students will have a big clean up day followed by a day off from school to relax. One area where perhaps anime is a bit misleading is the post culture festival party because it makes it seem virtually all schools have some big bonfire party. From personal experience the post culture festival party seems to be the exception and not the norm. I personally have never witnessed a bonfire, not to say it doesn't happen though. I have seen fireworks though happen afterwards and some K-On concerts or contests.
For 3rd grade students (JHS and HS go by 1st, 2nd and 3rd grade) this is most likely their last big event of their school life and after the festival it’s pretty much preparing for college so it’s a joyous and a little bit of a sad time. Perhaps not as well known, but colleges will also have culture festivals and at these they will serve beer and other liquor.
I might be willing to say that the culture festival is the single most accurately portrayed thing about school that you will see in anime.
As far as the sports festivals go it’s pretty much the same deal just with less prep, it’s only one day and more students don’t enjoy it. It starts the same as the culture festival, where as you see in anime the leaders will come to the front and the students have to decide who will run what event. This is a bit less democratic and a bit more “you run the long race”, “you should do the relay”. If you’re in a sports club expect to be busy. There is some prep work for the sports festival, like making a class banner, perhaps headbands and a few practice days so students know exactly how the events will be organized on the day of. If there is a more special competition like a dance, then the practice will be a bit more intense. Then on the day of it’s pretty much just a lot of running and games.
You will typically have so kind of teams, these can be broken up in any number of different ways from just all the first grade classes against each other, all the second grade classes against each other and so on. Also you could have classes 1-1, 2-1 and 3-1 as a team vs classes 1-2, 2-2 and 3-2 and so on. Less common, but you'll also perhaps see teams based on birthdays, whether it be months or seasons. These teams will be signified by a different color. The most common though is some form or another of different grouping of classes or just individual classes facing each other.
This again is another pretty much spot on depiction. Perhaps the one thing anime doesn’t do enough of is show the other events. There’s a lot more to sports festivals then just running. You’ll have botaoshi, a game where you get on people's shoulders and knock off other people's hats, jumping rope, dance, obstacle courses, tug o war, a pta event. These events normally don’t seem to get much screen time, but they certainly are just as big of a part of the day as the basic races.
So in closing if you’ve watched a school life anime you have a decent enough idea of exactly what a culture and sports festival are.