When I was in art school "hobby tunneling" was kind of a fad. Both the sculpture and performance art students got into it. Digging a huge hole or tunnel on campus was frowned upon, so it was that much cooler to pull it off. I remember one guy digging a giant well and another guy digging a huge tunnel by hand and literally living in it for days. The art school was 50/50 male and female and there were plenty of trends that both participated in, but only the men got into this particular art fad for some reason.