To get someone angry or mad. Usually used by kiddies in IRC and Games when cheating and other players get mad.
Some_Gamer: MAN, WHAT A CHEATER!
Some_Gamer: YOU'RE FKING GHEY
Cheater: Wow, it's just a game, stop getting so raged.
IRC_User: Dude, stop banning me, plz
Banner: Hahaha, so raged.