At MIT, this is called hacking. Hackers go out and explore the areas of MIT that most people ignore, like basements, sub-basements, ventilation and elevator shafts, and rooftops.
Hackers also introduce new students to this tradition by taking them on Orange Tours during R/O, when they first arrive at the Institute. Tour guides, (all named Jack Florey to save the poor, stressed newbies from learning more names) lead frosh around, introducing them to roof and tunnel hacking, while telling them stories about the great hacks of the past and the origins of the hacking traditions. They also introduce interested frosh to Hacking Ethics, which are one of the most important parts of any urban exploration