I need a fresh view to see if anything doesn't sound right like the fluency or just information in general.
Tell us something about you that will help your future roommate -- and us -- know you better.
I am a nerd and a jock. I love to spend weekends playing video games or messing around on the computer, yet, I can never go too long without playing some backyard football or shooting some hoops. I am known to spend hours attempting to solve a riddle while also, planning the weekend's activities with guys. Predictability is one thing I lack. I even surprise myself sometimes with the new things I do. As with most people, there is no exact stereotype that defines me. Some days you will see me eager to leave the dorm and go hang out with some friends. But on other days, I will be glued to the T.V. playing the newest and greatest first person shooter available. I love variety. You won't see me doing the same routine day after day after day. That's what makes me interesting.
Regardless of what I am doing, I always enjoy some company. I would consider myself one of the friendliest people you will meet. No matter who my roommate is, chances are that he and I will become close friends. I love making friends, even if we are polar opposites. I will always sacrifice my time to help others. If someone ever needs a person to talk to, I am the perfect guy. No matter what the problem or issue is, I love listening and helping in any way possible. For example, I was the first person one of my best friends came out to. He told me how hard it was to tell anyone he was gay but he was extremely realized that I accepted him for who he is and was always there for him. From that day on, he knew he could entrust anything to me. My friends always come to me for advice. Whether it's girl problems, or school stress, I always find a way to help them get things back in order. I want my future roommate to know that I am very excited to meet him and hope he feels the same.
"It seems to be hard to use such a short amount of space to truly describe who I am as a person. When forced to condense who I am into a short paragraph, simply, I am a nerd and a jock."
1800 characters certainly isn't a lot, so please, don't waste any of your precious character limit by complaining about how small the character limit is! Cut all of the redundancy and just start with "I am a nerd and a jock."
" I love to spend weekends playing video games or messing around on the computer. Yet, I can never go too long without playing some backyard football or shooting some hoops."
Combine these into a single sentence: "[...] messing around on the computer, yet I can never go too long without [...]".
"There is a very little chance that my roommate and I are not friends, no matter who they are."
You don't currently have a roommate (at least I would assume not), so you need to use future tense. Also, you will only have one roommate, singular, unless you're unfortunate enough to draw a triple, and your roommate will most assuredly be the same gender as you, so instead of "they" you need to say "he". Also, double negatives confuse me, so I would just simplify your sentence: "No matter who my roommate is, chances are that he and I will become close friends."
"I want my future roommate to know that I am very exciting to meet him and certainly become friends."
"Exciting" should be "excited." Plus, I'm getting a major sense of deja vu, since I already read and edited a sentence very similar to this just a paragraph ago...
Mostly, I feel like your essay is rather redundant and very "tell-not-show." You tell the reader that you're a great friend, but you never give any examples of that- couldn't you describe a time when you helped one of your friends out? Also, keep in mind that being "extremely good at arguing" might not always be a good thing. You might want to consider focusing on one specific aspect of yourself- either your diverse interests, or your friendliness- instead of trying to lump everything into one long and disjointed paragraph. I hope this helps- good luck with your application!