No. 1 - Robert Tappan Morris

Even if you know next to nothing about computer viruses, you've probably heard of "worms." That's because news stories about this particularly contagious (and therefore destructive) breed of virus abound.

Blame Robert Tappan Morris for it all.

Back in 1988, while a graduate student at Cornell University, Morris created the first worm and released it on the Internet. He claimed it was all an experiment gone awry, a test to see how big the then-new Internet was. The worm turned out to be more than a test: it replicated quickly, slowing computers to the point of non-functionality and virtually crippling the Internet. He was eventually fined and sentenced to three years probation.

Since then, he's earned his Ph.D. from Harvard and made millions designing software. Today, he's a computer science professor at MIT. Not bad.

Take our Hacker Quiz
Hack everyday objects with Kip Kay
The folks over at How Stuff Works know all about How Hackers Work