from Guerilla Software Development via CNET:
"This story is almost too cool to be true. A contractor working for Apple in the early 90s developed a graphing calculator application that took full advantage of the new PowerPC processor, but his project was cancelled while the software was in its early stages. He was out of a job, but his ID badge still worked. So he kept coming back to work, at no pay, for months, hiding from management, to finish the job, and dozens of Apple employees pitched in to help. In 1994, his app, "Graphing Calculator," shipped with the OS."
read the whole thing. It is a little long, but worth it.