I was hoping not to give it away completely, but you're right, it's hard to find anyway. basically it's a guided tour of some of MITs hidden places, rooftops, steam tunnels etc. usually advertised at the beginning of semesters & intended for incoming freshmen. I was hoping to either find one of the guides or someone who could tell me more about it. here's an article to give you an idea:
http://tech.mit.ed.../36orange.36n.html