I like this kind of story, told in wired

Avitzur sneaked into Apple's California HQ for six months to write a software program that, through luck and hard work, is still included on every Mac sold today.Unemployed and living on savings, Avitzur worked 12-hour days, seven days a week, to create Graphing Calculator in the unlikely hope that Apple would bundle it with new computers. (...)Avitzur and Robbins worked in vacant offices, avoided Apple security and gained access to the campus by tailgating employees as they showed up for work.(...)"We thought we were artists, and it was the responsibility of artists to get the work out there. That motivated a lot of what we were doing. But we were loose cannons and we didn't answer to anyone. There was no accountability. It was a lot of fun." Avitzur got a lot of support from Apple employees, many of whom had had pet projects canceled and were sympathetic. Skunkworks projects are a long-standing tradition in Silicon Valley. Many engineers work on personal projects in the hope they will be turned into products, even if they've been previously canceled. Companies like Google recognize the tradition, allowing staffers to spend 20 percent of their time on private projects.

Avitzur wrote up is experience here.