Subverting power structures: the incredibly true adventures of Graphic Calculator

Seems like software applications are becoming more famous than rock stars these days as more and more 'true stories' are published. The tale behind
Graphic Calculator is a true must read.

Ron Avitzur was an employee at Apple. But he wasn't an employee when he developed Graphic Calculator. He and partner Greg Robbins snuck into Apple facilities every day for months to work 12-16 hours on a project they weren't getting paid for. And it worked. They finished in January 1994, and Graphing Calculator has been part of the Macintosh ever since. "Teachers around the world use it as an animated blackboard to illustrate abstract concepts visually. It shipped on more than twenty million machines. It never officially existed."