I own few online games sites, my last project is http://www.ewargames.com , Ewargames.com is all about war/fighting/shooting/action site.
Cuéntanos a qué tipo de público quieres llegar
The site is for males 13-25, who likes to play online games.
The theme is War, which means guns, choppers,tanks ,soldiers,bullets combined in the logo will add , but its NOT a must.
It should be realistic and rough, you can use bullet holes or anything else.
Here's a nice reference to look at for the logo's main idea ( try thinking of it with a war theme)- http://packed.com/