When I was a little girl, a tree with these strange green fruits grew outside of my second grade class window. They were about the size of large oranges or grape fruits, and it was a part of the school yard that we weren't allowed to play in, so I never really got to investigate them up close, and they would just lay there on the grass like discarded brains. No one knew what they were called, and in fact, no one really seemed to care. I never saw these strange green fruits (inedible, I assume) growing anywhere else, until I moved to my current neighbourhood a few years ago and someone down the street has this strange green fruit tree in their yard. I still don't know what they are called -- something orange, maybe, if I remember that gardener guy on the radio that day that he mentioned something about them. They have a strange citrus smell that matches their strange green fruit-ness.