All the Data: Photo by Tom Schierlitz

It's July in Las Vegas, and the relentless midday desert sun has already pushed the outside temperature into three digits. But here inside the Alexis Park Resort, it's cool and dark. The bar is open, and the room is beginning to fill up. It's 1 p.m., the big game has just begun, and, as you'd expect in the world epicenter for sports gambling, the room glows with the light from dozens of screens catching every nuance of the action.

But these aren't television screens, they're laptops. And the motley assortment of guys peering into them and busily clicking away at keyboards aren't gamblers looking to score some last-second intel on the game, they're hackers–and this is the game.

Welcome to Def Con, the self-proclaimed "largest underground hacking event in the world." That´s a tough claim to verify, what with the fetishistic value the attendees and organizers of such gatherings place on privacy, but there is no doubt that Def Con has exploded in popularity in the 12 years since a 21-year-old hacker dubbed The Dark Tangent (a.k.a. Jeff Moss) decided to launch the event as a way to meet a bunch of friends he´d only known online. About a 100 such friends answered his call for that first conference in 1993; at the 2004 Con, every one of the 4,000 preprinted entry badges sold out early. To get one, all you needed to do was show up at the door, $80 cash in hand.
No preregistration, no names, no questions asked.

And what do The Dark Tangent´s underground army of friends get for their 80 bucks? They get a three-day program packed with panel presentations on everything from the latest security research to tips on hacking your car. They get a chance to test themselves in a full slate of competitions, including War Driving (a scavenger hunt to identify unprotected wireless-access points in Las Vegas), Wi-Fi Shootout (a contest to establish long-distance wireless connections in the desert) and Spot the Fed (a game that awards T-shirts to those who successfully identify government agents in the crowd)-not to mention the hallowed annual coffee-brewing challenge (these guys are serious about their java). And they get their choice of three swimming pools, at least one of which is guaranteed at all times to be the scene of a boozy party, complete with DJ.

But the signature event of Def Con, the sun around which all else orbits, is the game just getting under way in this slightly seedy banquet room: an electronic version of Capture the Flag. Eight elite teams of hackers have advanced out of the 21 that entered an earlier qualifying tournament, and each team occupies one set of the conference tables that ring a nine-foot-tall scoring center, each set of tables littered with laptops and the team´s server, or "game box." As in the game we all played in summer camp, the object here is to grab your opponents´ flags while protecting your own–but these "flags" don´t exist anywhere except the virtual worlds inside those servers.

Def Con´s Capture the Flag competition is the Super Bowl of hacking, though it must be said that a room full of pale, black-garbed geeks typing away and piling up Red Bull empties doesn´t exactly call to mind the smashmouth physicality of the gridiron. On the other hand, you´ve got to give the athletes assembled in this room the nod when it comes to stamina. Football´s superstars need to be at the top of their game for only about four hours. The guys here are going to be staring into these laptop screens for the next 33 hours.