One of our Project Managers was recently promoted to a System's Manager, and given an office.  He decided that he was going to bring a piece or carpeting in (because the office he was getting had none).  It was a nice piece of green carpeting.  One of the guys here sugested that we make lines on it like a football field; the idea just balooned out from there.

There were many people involved with this little task.  The important thing is that we had fun (and it didn't really take all that long).