In 1983, Mark Abene [wiki] was nothing more than a beanie-wearing mall rat with too much spare time. He didn't own a computer, so one day he wandered into a Radio Shack, cozied up to one at the store, and tapped out a few commands. And that's how his hacking habit began - as simple as that. By 1984, with echoes of Orwellian symmetry, he was already using his own PC to sneak into other people's computer systems. While his parents were busy upgrading to a touch-tone phone, Abene was figuring out how to redirect traffic between switchboards.

Then the world learned what a pimple-faced intruder with simple Radio Shack gear was truly capable of. In 1991, in response to the AT&T telephone system crash that left 60,000 customers without a phone line for nine hours, federal authorities burst into Abene's bedroom, guns drawn, and confiscated his computer equipment. Although Abene was ultimately acquitted in the scandal, authorities nailed him for related mischief. Today, his phone hacking, or "phreaking," is an infamous milestone in hacker history. At just 19 years old, Abene (a.k.a. Phiber Optik) became the first hacker to serve time in a federal prison.