This Saturday, a dozen guys are going to waste each other. No, it’s not a local fight club, but the latest in macho tech: a Halo Party. Played with the alien-splattering videogame Halo, Xbox’s best seller, the parties involve up to 16 people simultaneously connected to four Xbox game consoles (with system link cables). Players team up for carnage-filled rounds of virtual games like Capture the Flag or Slayer. The thrill? ”You hear the agony of the person you just killed,” says design manager Josh Milligan, who powered up the effects for a recent gathering by hooking the Xboxes to projectors and plugging the game into surround-sound systems. ”I have a ton of friends who are asking about the next [party].”