Phreaking, The First Movement
Even before trying to access the computers of the US Navy, geeks had their methods for shocking people and making themselves known. As mentioned just above, John Draper was one of the first hackers, and gained his fame using a child's toy.
A Magic Whistle
In the late 1960s, after discovering a whistle inside a box of Cap'n Crunch cereal, he started his exploits. He had just become aware that those whistles were capable of generating a 2600 Hz tone, which was the frequency used by telephone lines to signal that a line was active. John Draper became one of the first users of this technique, which was rapidly christened "phreaking".
Draper's method was quite simple. First, he dialed a long-distance number, and while the number was ringing, he would use the whistle to send a tone at a frequency of 2600 hertz. This tone was similar to the one used by the telephone network to signal line status. By imitating this signal, he would make the telephone exchange believe he had hung up and that the line was free, even through the exchange had not received the actual signal corresponding to a call being hung up.
The Instigator of a New Movement
Draper's activities were discovered when his telephone company realized that his account showed strange billing patterns. An investigation disclosed the affair, and Draper was arrested in 1972. Prosecuting Draper took a long time, because it was the first time in history that the legal system had dealt with this type of fraud. Four years later Draper was sentenced to two months in prison.
His activities gave birth to a whole movement surrounding phreaking. A hacker and phreaker group arose and gave themselves the name "2600", and many other people also tried to find ways to stop paying for telephone calls.