One of the first examples that I came across where Beethoven's Fifth Symphony was being used in modern media/cinema was in the movie The Breakfast Club which came out in 1985. The tune that the students are whistling at first is "Colonel Bogey March". So why do they suddenly stop when the principal walks in and this is where one of them switches and whistles that short-short-short-long theme. So why is it that he whistles this theme? Beethoven refers to the opening theme as "fate knocking at the door" and by the "fate" he is referring to his worsening deafness. Beethoven stated that "seize Fate by the throat; it shall not bend or crush me completely". This directly relates to what is happening in the movie so that the theme fits in perfectly. The kids are all whistling a happy tune, but then the principal comes in and ruins their fun. This is when the kid changes to whistling the short-short-short-long theme(at 31 seconds). Him whistling this theme is relating to how the principal is ruining their fun and holding them back just like Beethoven's deafness made his career harder and held him back. So even though the kids are in a bad situation already as it is, right when they try to have a positive outlook the principal comes in to remind them where they are, just like Beethoven's deafness as it gets worse. (see video below)
This next example that I came across was a AmPm commercial from 2012. In this commercial the two guys use dispensing soda to replicate the same short-short-short-long theme that was whistled in The Breakfast Club. So the same part of the composition is being used in both examples, but in completely different environments. While the mood in The Breakfast Club example shifted from being happy and cheerful to sad and down when the theme was played, in this example they are using the theme in a happy joyful way. So why would they choose to use this song rather than a different one? For this commercial I think that they used it just because of the familiarity of the theme. There isn't really any other reason for them to be using it in this context and there isn't a deeper meaning behind it other than it's something that is familiar to people. So they just used it as a form or marketing technique in this circumstance. (see video below)
This example was found in a cartoon called Mr. Bean. You may be familiar with this title from seeing on of the Mr. Bean movies that have recently came out. The movie Bean came out in 1997, while the movie Mr. Bean's Holiday came out in 2007. So why is Beethoven's Fifth Symphony being used in this cartoon show? Mr. Bean is known for being a somewhat whacky/odd person who does a bunch of crazy funny stuff. In this clip he is trying to learn how to play the Fifth Symphony on his piano that he just recently got. I think that they are somewhat poking fun at how such a simple short four note melody has become so famous and widely known. Mr. Bean can't seem to get the short-short-short-long part correctly so he hires a instructor to try and help him out. Even after hiring this instructor he still cannot get it correct and they have to try and find another solution. I think that they used Beethoven's Fifth symphony because of how famous and simple the "fate knocking at your door" theme is.(see video below)
This next example is from the movie Austin Powers: Gold Member. Now I will warn you that there I a minor curse word or two in this scene, but you only have to listen to is for a little bit to here the song playing in the background while they are talking. Now the song that is playing in the background isn't quite Beethoven's Fifth Symphony though. The song is actually called "A Fifth of Beethoven" by Walter Murphy. Now this is just a 70's disco twist on the very famous classical piece. Why I think they picked this piece is for two main reasons. The first being that they wanted to properly set the mood. The movie is suppose to take place in the 70's so it only makes sense to use a 70's remake rather than the original classical because it would set the mood out of time. The other reason goes back to the familiarity. It's still a song that people know and are familiar with so it gives them a sense or security. This clip also shows you the many ways at which the song has been altered over the years. You can find remixes of Beethoven's Fifth Symphony from a disco one, as shown here, all the way to a modern dubstep remix with bass drops and electrical an electoral twist. This just goes to show you that you could have been exposed to this music in a completely different version than the classical one. (see video below)