There's an unwritten rule that any food left unguarded in a kitchen or common area that is not inside a refrigerator is free for the taking. One of the teams in my building had a ton of Indian food catered in. As soon as those people started leaving, word spread amongst a few key members of my team, and a few minutes later, I had free dinner. The other denizens of the building descended upon those trays like wolves.
I had some chicken vindaloo. I've never had something cold taste like burning before. That's a curious sensation.
There's an internal service that apparently used to be very popular where you can go and register leftovers so that people in nearby offices can quickly dispatch them. I don't think it's used anymore; I heard stories from older employees that half-eaten sheet cakes would disappear in minutes in that service's heyday.