I suggest transferring the time you spend on video games to actually improve your grammar. Trust me, the online community in Call of Duty, if anything, will harm your English.

It's a bit more work, but if you really feel like improving your grammer, might I suggest finding a genre or author that you like and picking up reading as a hobby? Immersing yourself in (correct) examples tends to be a rather effective method that works for pretty much any language. (Unfortunately, this doesn't work for people who don't learn from example well, like my poor sister who loves to read but still writes horribly orz)

Mad prop for giving a good advice and I'll be reading a book and storyline in the video game boost my grammar up, cheezmaster.

Thanks for giving a good advice that I'm not sure about to pick a different genre on books. I have interested in reading type of genre on books are comedy, classic literary, and science-fiction. What books do you recommend me to read, hakimiru.

I'm sorry. I can't hear it and you could turn it on high volume making me feel very better to hear, mission.

I think any book that keeps you interested in reading it will help to improve your grammar.

I love the Sword of Truth series by Terry Goodkind. It's a fantasy/magic story. In addition to being fun and exciting to read, the stories explore relationships between lovers, families, friends, and enemies. You can probably find the books at your library. They are also fairly inexpensive on Amazon.

If you liked the world of Assassin's Creed, there is an accompanying novel called Assassin's Creed: Renaissance. There are Italian words mixed into the story (it's not overwhelming) and there is a glossary to look up their meanings in English.

I think any books geared toward young adults would be a good fit. The stories are usually short and the writing would take grammar proficiency into consideration. I'm not familiar enough to recommend any, but this would be a great question for a librarian.

Hope that helps! And I hope you read the Sword of Truth books. They are so good!

Ender's Game.

Have you read some sci-fi classics like Farenheit 451 and Nineteen Eighty-four? Also, The End of Eternity and Brave New World are a couple good ones.

Your local library should probably have all of those on the shelves, as well.

Treehouse Gamer beat me to my post. Ender's Game is a vastly interesting book. Very well written and it's based around a group of children training for war in different 'games'.

Should you like Ender's Game, I would also recommend Ender's Shadow, which is a companion novel from the point of view of someone else from Ender's Game.

Slightly more on topic, should regular novels seem too intimidating for you, start off smaller. Try well-written graphic novels. When I was in middle school, I never read anything I didn't have to and my verbal skills showed. So my mom took me to a bookstore and let me pick any books I wanted. I ended up getting a bunch of Choose-Your-Own-Adventure and R.L. Stein's Goosebumps books. But once I read through those, I actually got real into reading.

[If interested, PM me and I'll give you some excellent zombie/end-of-civilization books]

A best-selling book is like "Twilight" or "NASCAR Nights."

On the other hand, if you're looking for well-written books, anything by Sharon Shinn, David Rothfuss, Naomi Novik, Orson Scott Card (damn his anti-Semite soul), or Jane Lindskold should do.

"Best Selling" doesn't mean it good. Hence Twilight.

While books such as 1984 and Brave New World are fantastic, I agree with Frankski. You should probably start smaller, then move onto those books. I also recommend writing more. Try your best to improve each time you write something new.

The Overton Window by Glenn Beck

To follow up, here's a big list of best books for young adults according to the American Library Association.

Someone mentioned R.L. Stine's Goosebumps series. I remember reading those when I was younger. They are easy to read and interesting too.

I used to read mostly fantasy so you'll probably be getting better recommendations within your specified genres from everyone else, but I recall this series being interesting. http://en.wikipedia.org/wiki/The_Tripods
And as several people have already mentioned, starting small with something easier is a good idea if some of these suggestions seem too intimidating at the moment~

I totally forgot about the age thing. Goosebumps is a good choice, as well as the Animorph books, which are more sci-fi oriented.

Thanks for telling me some recommended books, guys. I remember Goosebump book was a great choice for me to read when I was in the high school. I'll try to read more books for every day.