Can be used to describe anything cool or uncool, loosely. It is however most fittingly used in situations that involve some sort of event happening twice or to two sujects at the same time, or quickly in succession - hence sounding like doubles.
In FIFA 2009, when tackling two players with one sliding tackle: "Damn! Doobles!".
When someone makes a stupid mistake in FIFA 2009, it can be considered doobles.
When kicking someone in the nuts.
The most retarded person you know
it derives from a combo of Dumbass and a variation of Noob.
also, usually a script kiddie
Doobles: Look at this DELL FAIL!
Doobles: omg i'm so 1337 gaiz.