Way back in 1999 I worked on the largest project of my life. We had 60 developers working non-stop on a huge portal application for a really large oil company. It was insane - the company I was working for couldn't get enough developers, and - to keep us working - they provided us with all of our meals and would get hotel rooms for people around the work location so that people would work later.
Every day, new people were coming in to redesign the project. We had marketing droids, people from Rational - anyone they could hire to drive the deisgn of the project in a new direction. We were constantly having to change the design process based on the opinions of whatever company was in to offer the newest ideology.
Over time, as you could imagine, the code got really, really bad. Once a modular Java project, it started to look more and more like C as people who had never worked on the project started being assigned new sections. I say that there were 60 developers, but this was the average - people were being moved in and out on a revolving door basis, flown in from India and moved right back (sometimes after finding out some of the guys didn't really know how to program).
On top of the developers, there was a team of graphic artists, database gurus, server people, and an enormous management team. I worked on the project for 6 months until I quit, and every week it seemed that I would have a new boss. I remember one week, one of the bosses showed me a design chart that he had come up with. It was a complete redesign of the current system (4 months into the project) with various buzzwords highlighted in yellow marker. His idea was that if he could incorporate as many buzzwords into the project as possible, the project might gain the respect of his peers and he could start writing articles for technical magazines.
Let me stress again, this was a big project. I have worked on larger teams than 60 people before, but I have worked on a project that has produced that much code in such a short time.
Since I quit, I found out that the company I worked for never finished the project and was merged into its parent company which was shut down due to fraudulent accounting practices.