Fundraiser Carnival

When a school has a fundraiser, they need ideas how to carry it out and bring in big money for the cause. One of those ideas, in Real Life as well as on television, will include a carnival, and this is the option that wins out overall. Why shouldn't it be? carnivals make money, and money is what the school needs. If done properly, carnivals can have a lasting effect as they can make a large number of people aware of your cause at the same time.

There are other situations in which this can apply, for example:

A birthday party!
A senior send-off!
A major holiday!
A prom!
Just for the hell of it (Carnivals are awesome!)

With any situation, the carnival is always chosen as a proper venue. And, in all situations, the school will always have enough money to pull it off, even "poor" schools. A requirement for most fundraiser carnivals is that some sort of crazy circumstances will mess them up.

Not to be confused with the carnival-like Japanese Cultural Festival events that often appear in anime high schools; those are actually common in Japan.

Important features of the carnival usually are:

A dunk tank
A ferris wheel
A ring toss
Cheap, unsafe rides (optional)
A kissing booth
That game where you have to throw a baseball at some bowling pins to win a comically large stuffed animal for your date to impress her.

If a dance is held to raise money for any reason, it is a Charity Ball.

Examples of Fundraiser Carnival include:

Film

In Daddy Day Care, the two main characters need to buy a property to save their daycare business, so they throw a carnival.
There's a school carnival in the film version of Grease, although it doesn't figure into the plot.
In Never Been Kissed, the school throws a carnival for the seniors (or something like that).
There's an on-campus charity fund raising carnival of sorts at the end of Revenge of the Nerds.
There's a childrens's charity fundraiser featured in She's the Man. It's while she's there that Viola first kisses Duke (at the kissing booth) and falls for him.

Literature

The Macdonald Hall book Go Jump In The Pool has the students running a carnival to raise money to build a swimming pool.

Live Action Television

The Brady Bunch once built a Dunk Tank for a school carnival.
There's one in the Corner Gas episode "Cat River Daze." Davis and Hank are both so excited about the dunk tank that they compete with each other to annoy the townsfolk so people will want to dunk them.
Degrassi the Next Generation has had at least two of these episodes.
Shows up briefly in Everybody Hates Chris.
In George Lopez, the family works the dunk tank at one of these.
In Life as we Know it, the boys attend a carnival, which may or may not be for the school.
In Married... with Children, after Peggy goes overboard with yard sales, Al decides to have one himself. It fails spectacularly, so he turns the back yard into "Bundyland".
The third season episode "Bulletin Board" of Mash has picnic for the entire staff and a nearby orphanage. With some elements that could appear on a carnival: Klinger has a kissing booth. People can buy snacks. There's a sack race and a spoon race. During a game of tug of war, where most of the major cast ends in the mud pit, incoming choppers abruptly end the picnic. The goal wasn't to raise money, but morale.
In The Monkees episode "Monkees Mind their Manor" there is a medieval faire to raise money to buy Davy's inherited Manor for the local villagers.
Used in the second episode of No Ordinary Family.
The Homecoming dance in Pretty Little Liars was this combined with a Charity Ball.
In That's So Raven, Raven works the dunk tank at a school carnival.
Veronica Mars's Neptune High had a Winter Carnival to raise money for the senior trip. Justified in that it's a very affluent school district.

Print Media

The Onion has parodied this at least once, with a mention that some years it actually costs more money than it brings in.

Theatre

In the Heights: The whole neighborhood has a carnival after the power goes out.

Web Comics

Eerie Cuties got a bonus story centered on Layla's kissing booth at a Fundraiser Carnival. The comedy being naturally derived from the girls acting in character: Brooke complaining about how demeaning the entire kissing booth concept was, an innocent succubus and the local Alpha Bitch wind up in the booth and cause hilarity in their own unique ways. It ended with Layla in the booth, and Brooke thinking to force her to back down by buying a ticket herself. To her surprise, Layla was willing to kiss a girl for this, and that this only got more customers because Girl-On-Girl Is Hot.

Western Animation

Daria has an episode where the library roof collapses, so they hold a medieval fair to raise funds for its repair. What's interesting is from the size and scale of the fair you can be sure they're spending about the amount they could fix it with in the first place.