I have a similar story from Virginia Tech. Last year while I was a Freshman, a friend on my hall (who shall remain anonymous) showed me some pictures of the mischief he got into as a Freshman himself by sneaking into the campus steam tunnels. The pictures he showed me were pretty similar to those seen on this site, it was a tunnel corridor with pipes of various sorts going through the top. There were also portions where he had to crawl on his belly to make it through, and let me tell you from the pictures it looked quite hot down there!
Unluckily for him, motion sensors are installed in the tunnels to keep explorers out, and he tripped one of them. As he tried to come out of one of the manholes at 3'ish AM, a police squad car was waiting nearby. Needless to say, he got booked by campus security and had to do a lot of volunteering as sanctioned by Judicial Affairs in order to avoid getting kicked out of school; he's still here and has the awesome pictures to prove it!