To be honest, in the past I used to spent a lot of time on video games. As I remember those were "Battlefield - 2" and "L4D 1-2" servers and that was when my first english practicing had happened before going to Europe for almost three years. So, the conclusion might be that if you like gaming then you actually can join some russian servers and develop your language skills.

But.......... (like Jeremy Clarkson from BBC Top Gear always says ) there are a couple of devastating problems.

1. While we played on the most popular russian server we almost never tolerated foreigners, because the ability to communicate perfectly was important. We normally were making exceptions for some players from Poland, who understood russian a little bit.

2. These days I don`t play any games, but still do watch some famous gaming youtube channels like "Seananners" (Adam Montoya). The trouble is that in-gaming conversations are only good for short type of expressions. "Get over here", "run away", "burn in hell" - pretty soon you`ll start to understand these sayings perfectly. But your vocabulary won`t be rich.

So, like in fitness, you should not only develop your arms, but legs too, not only the power, but stamina as well - same idea is in languages. Try to read some intellectual novels. Watch classical movies. Write letters. Talk on camera or via skype.

If you only play games - you may sink in illusion that you are already fluent and stuck in development...

P.S. I highly recommend you to watch on a day-to-day basis the following russian walkthrough channels. Different games, updates every week. And the authors are older than 20 y.o., so normal sence of humor and common useful thoughts are guranteed.
PomodorkaZR - YouTube
RusGameTactics - YouTube

upd For those, who are fond of chess like I am http://www.youtube.com/user/Super300476 - extremely funny commentaries from Alexander Gelman (FIDE Master).