The word used to refer to the best (awesomest)game in the world. The game can be of any genre. The word Rush derives from people wanting to play it so bad that they decide race each other.
Casey: Hey..do you know of any decant games out there?
Kasene: Hmm.. Lets see...Oh!I know one. Its called Conquer.
Joao: WOW! CONQUERRUSH BABY!