At Debconf 9, Steve Langasek delivered a talk on pam-auth-update, which included a tongue-in-cheek slide about how it had come to be. He pointed out that this project had required about six years of “thinking” and two months of actual development… More here
Debian is a good example of a large open source project with well established patterns of work. Most of the work in Debian is divided up according to packages, and a designated person or team is responsible for each package. This autonomy is a part of what makes Debian development particularly rewarding, as it fosters a sense of personal ownership.